I am having a hard time understanding the policies of this site.
No problem. That's exactly what the Meta site is for :-)
According to this:
This site versus [wordpress] on Stack Overflow
this site's purpose and mandate is to be "the place" for Wordpress related questions.
Yes, and the definition of what "the place for WordPress related questions" means can change over time.
For example, when we first started we encouraged questions about theme/plugin recommendations. But that was later discouraged among the larger SO/SE community, so we're now beginning to close some of those older questions because, in the grand scheme of things, they're too narrow in scope to be of much future use anyway.
What I see when I use this site is large numbers of topics, everything from the business of theming to recommendations of various types to using html5 semantics in WordPress being declared off-topic.
Sometimes they are, sometimes they aren't. It all depends on the context of the question, and I realize that's not much help for deciding ahead of time whether or not to ask the question.
Generally, the rule of thumb is to look at a question and see if it's any different if you exclude WordPress from the question. If your question on HTML5 semantics would apply to WordPress and Drupal and ASP.Net and any other framework, then it's probably general enough to live on SO instead of the WPSE.
If removing WordPress from the question means it won't make any sense at all (i.e. you're asking about core WP functionality or how a specific plugin modifies the markup of a page) then it would be on-topic.
It's a bit of a fuzzy area, which is why we ask the entire community to pitch in when making such a decision.
The moderator closes the question and I don't get to decide if I want to answer the questioner or edit the question. I see a small number of people deciding for everyone. Why? I wish the moderators and voters would be less quick to judge, more constructive and slower with the down vote.
If it was your question, you can always go back and edit it even if it's closed. Closing a question is the community's way to signal that there's something wrong with it - maybe it's too general, maybe it's too specific (i.e. applies only to a narrow time/situation), or maybe it's just unclear what's being asked.
If you edit your question, you can ask for it to be reopened. The moderator staff are more than willing to reopen a clarified question.
Downvotes are the community's way to say they think a question is of poor quality. It's nothing personal and not an attack against you. I've had plenty of my own questions downvoted, too. If your question was erroneously downvoted, someone will likely upvote it in response to balance it.
Remember, a downvote also negatively impacts the person leaving the vote, too; if someone cared enough about your question to take a reputation hit themselves, it means they're trying to help. (This used to be true, but has apparently changed in recent months.)
How does excluding a wide range of topics that many people do find interesting and valuable differ from censorship?
Let's be very careful with terminology here, because "censorship" carries a lot of emotional weight for many people in this community.
First of all, closing a question as off-topic doesn't remove it from the site. It just locks things down so the original asker can take some time to edit their question. It does lock out answers, but not to censor anything - often times an edit will substantially change the nature of a question. It's incredibly confusing to people looking for help to see a slew of answers that seem wholly unrelated to the question that was asked.
Does this site want me to say "I don't know which element to use to express this wordpress widget concept. I should ask at Wordpress Answers." Or "I don't know which element to use to express this wordpress widget concept. I won't ask Wordpress Answers because they won't help me and they might flame me!".
We want you to ask WordPress-related questions. But as I said above, if your question is the same with or without WordPress in it, is it really a WordPress question?
Secondly, no one here is trying to flame anyone. If they do, the moderators are very quick to step in to keep the conversation civil. If we fail to do so, there are super-moderators from SO who step in just as quickly.
Please remember, close votes and down votes are not personal attacks. Nor are statements that someone feels your question is off-topic. We're communicating in text here, and most of the tone we'd normally convey in speech is lost in this medium.
So my question is: is it really the right policy to shut down wordpress related questions as often as you answer them?
Once again, some "WordPress-related" questions aren't really WordPress related. Just because a site happens to run on WordPress doesn't mean every question the site administrator has is a WordPress questions.
Sometimes a weird issues with your site is an artifact of the browser. Sometimes it's a jQuery conflict. Sometimes the alignment issue in a sidebar is caused by a bad CSS rule.
In all of these cases, though, you and I won't necessarily know until you ask the question. All of these issues might very well be WordPress issues, so please keep asking. If we find out that no, it isn't a WP issue, then we can close the question later - or potentially migrate it to a StackExchange site more suited for the topic at hand.
Should you be telling questioners (as I have been told) to ask their questions tagged wordpress on other sites? Who should decide?
Sometimes, yes. But only when the WordPress question isn't really a WordPress question.
Does it make the site more usable or useful to be rude?
I went back through and looked at several of the questions that have been recently closed. No one was being rude when they suggested things were off-topic. They were stating an opinion, or providing an explanation for their close-vote or down-vote.
Everyone needs to remember that people come to this site when they're stressed about a problem and looking for answers. Getting a "this isn't the right place to ask" response right out of the gate is tough and just adds to that stress.
Could we all be a bit more polite when offering feedback? Sure. But no one is being outright rude in their critique.
I volunteer on SO, and would here too if I found this site more friendly.
We'd love to have the help!
Is this site trying to narrow it's user base?
No, but we are trying to refine our scope. There are questions asked here every day that dilute our content.
Questions about WordPress.com (a hosted service) are off-topic because they have their own support channel (and there's not much we can do to impact change there in the first place).
Questions about premium themes/plugins are on-topic, but many times we'll leave comments that you should go to the premium support channel because few of us (if any) will have access to the system you're having issues with.
Generic PHP/HTML/JS/CSS questions are off-topic because they're already handled by Stack Overflow.
Our objective is to be the place people come for WordPress-specific answers. Not PHP scope questions, JS event questions, HTML markup questions, CSS selector questions, etc. There are better resources for those available. But questions about WP core functionality (hooks/filters, templates, plugin design, rewrites, etc) are exactly what we're looking for.
I feel the need for another site to answer my Wordpress theming questions because this one excludes too many.
That's too bad because, really, we need some good theming questions. But remember, they need to be hinged on WordPress or they won't come across as on-topic. Some of our power users are members of the official Theme Review Team, so we're more than ready to take on whatever questions you can ask.
Who is this site for? I keep getting the vibe that it isn't me.
I hate to say this, but you might be right. This site and community isn't for everyone, but I would still encourage you to stick around and give it a second chance.
I rarely drop in the official forums on WordPress.org for the same reason. They aren't a good fit for me, the way I ask questions, or my workflow. So I come here instead.
But this is also why we have so many tools and resources available - some people do better with a Q&A site that has a clear scope. Some do well with a freeform forum. Some do better live on IRC. No tool is superior to the others, but each one might be a better fit to a particular person than another.