[lucb1e]

Stackoverflow.com -> help -> search "editing" -> top hit: https://stackoverflow.com/help/editing

See the itemization of reasons to edit a post for. It also explicitly mentions that the meaning of the post may not be changed. You can, as the owner, also always roll back edits. Another option is to take it to the meta site and voice your complaint. One of the reject reasons in the review queue (note that moderator's edits don't go through the review queue) is if the edit changes the meaning of the post; the edit system is really meant (as the page says) for fixing typos and on occasion updating/adding information like if the post became outdated or to consolidate info from comments.

Everyone can also see the revisions of any (non-deleted) answers and questions, so if someone changed the meaning, it clearly says "person x edited this post" (right next to the original author's name) and you can click that link and see who actually said what.