If it were just exclusives it likely wouldn't have made people as mad.

But numerous games were literally removed from Steam after months of open preorders to become Epic Exclusive. Only after backlash did they even allow those who preordered to keep the game on Steam.

Same with breaking up games in a series between multiple platforms. Generally exclusivity meant a brand loyalty you could expect. So if you liked Ratchet and Clank games, you were safe buying Playstation. For an example of this elsewhere, the Monster Hunter fandom is still screaming and seething about World being on PC/PS4, and now World fans are seething about Rise going to Switch. Epic threw a huge wrench in that for a few major series.

Not to mention the Epic Store was barely functional and missing a huge number of basic features for a long time, like a shopping cart.

Little things like that taint a reputation and turn people against your company and Epic hasn't really done anything to undo their negative rep. They just keep throwing money at more exclusives hoping to bribe you into liking them.