Did you read the post? It clearly says that destroying the lamp things will result in some strange visions in your endings and helps unlock another secret ending. thats all it says, I don't get why you're complaining about broken saves and whatnot.
Im no expert but I know a thing or two about renpy. The choice activates a persistent variable, probably needed to unlock that ending. The endings are outside of the story or the main game in their own unlocks menu. I noticed that the replay gallery works in the same way, it's a basic way of making renpy save variables. I think he's giving people early warning that if they want to unlock that ending they should do this. I'm curious to see what the ending is about, sounds interesting so far.
I don't know, I think part of what was initially good about Cursed Affection was the element of corruption. You start with a pregnant girlfriend, but it becomes a part of the story that the MC is getting seduced by these women and cheating on his partner. Part of the appeal was the sinister vibes of the story imo.
uhm... I think links in the OP are for the same version... one says "clean", but it seems to be the same? same file size, same AI animations... is there a mistake or are there other differences?