I just found someone even saying that Nemlei used copyrighted material to make the settings and music for some of their first games and that would be the reason for removing them, lol
Viewing post in The Coffin of Andy and Leyley - Fan Translation 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)