People can edit your posts, but they aren't automatically trusted to do so.

You need 2000 reputation to be allowed to edit questions and answers without review.

During review, one of the reasons to reject a pending edit is:

This edit changes too much in the original post; the original meaning or intent of the post would be lost.

So, people who would make such drastic changes to your post would most likely be corrected quickly. Users who don't have to have their edits reviewed are trusted to know how to edit contributions properly.

People can edit your posts, but they aren't automatically trusted to do so.

You need 2000 reputation to be allowed to edit questions and answers without review.

During review, one of the reasons to reject a pending edit is:

This edit changes too much in the original post; the original meaning or intent of the post would be lost.

So, people who would make such drastic changes to your post would most likely be corrected quickly. Users who don't have to have their edits reviewed are trusted to know how to edit contributions properly.