Not just controversial or political. I've added edits with valid sources to non-political and non-controversial pages only to have them immediately reverted by a zealous editor who looks things just as they are.
I had edits with valid sources be reverted and then added by the "owner" of the page. Wikipedia honestly is a mess in my opinion for contribution. I'd prefer if edits could be voted upon by the community to be approved or not instead of someone being able to straight up edit it and straight up revert edits.
This is my experience. I fix an error on a page (and not a controversial page, and just fixing an error in some math) and it is immediately reverted by someone's bot. A few hours later the moderator puts the edit back in. Probably pretty difficult for someone to break into the "star wiki editors" list these days.
