If it had been because of the incest in TCOAAL, Nemlei would have simply deleted the Demo of this game and not the entire profile with all the other games. According to some YouTube and Reddit comment threads, there seems to be something shady behind the removal, like some compromised personal info (a risk of doxing) in the content of one or more of the old games or the personal data linked to the account registration that motivated Nemlei to delete it. Others say that Nemlei did not want to moderate the reviews or maintain support of the old free games on this platform since they didn't generate any income.
Viewing post in The Coffin of Andy and Leyley - Fan Traduction FR comments
Nemlei erased all the games (not only the older ones) and except for Jack-in-a-castle, they are all free, and you are allowed to use copyrighted music as long as you don't market the product
And for Jack_in_a_castle, it was on Steam, and steam usually verifies if there's any copyrighted content in the games
It's also known that Nemlei gave the rights on TCOAAL to Kit9, and Kit9 published a statement saying that Nemlei terminated her online presence due to doxxing and death threats (because of the incest ending in TCOAAL chap 2)