I'm one of the two users who rejected your edit. Not the native English one though. My Native tongue is Afrikaans. Hahaha. Pulling G.M.'s leg a bit here :-)
On the serious side, according to me the edit was too minor and the edit did not really improve the post overall quality such, that is why I rejected it. The post author also has the opportunity to accept or reject or skip an edit on his post, which he did.
We try to keep minor edits to a minimum, as posts with excessive edits gets community wiki'ed, and that particular poster looses all reputation and future reputation on that question or answer.
You have to remember as well, most top or high reputation users don't speak English, so we at times do make mistakes with edits and in our posts. You as a non English speaker would know that. Even the native English guys do get it wrong at times.
On edits, we need two rejections to fully reject an edit, so on your post, the edit was rejected by me another user whos native tongue is Spanish.
As you are interested in constructive edits, @toscho has written a comprehensive guide to edits. It must be noted, we all still have our own descretion to edit, reject, approve or to suggest edits on merit and act within the guidelines. This rejection should not defer you from doing future edits, but encourage you to be a better editor. Feel free to read this post on edits