It's very rare to see a game dev and their games be so universally hated by everyone. Even games that are constantly milked beyond recognition like taffy tales have better ratings as well and more positive interactions with the comments lol.
It is indeed quite odd if you're only looking at this thread, in which it seems everyone is just piling on the dev for relatively small reasons.
With that said, I'd say the dev earnestly gained that reputation from the non-animated version of this game. I'd still categorize paywalling save slots as one of the funniest and dumbest ways to monetize your game, among other things that I can't remember. And their sarcastic and snarky way of replying to people complaining certainly did a good job antagonizing them. As bad as the paywall was, I'm confident the dev's attitude in this website contributed more to their bad reputation.
Not that it matters though, it seems they're doing quite well financially from the patreon numbers.