GOG has removed some games from the shop - an infamous case being the three Fallout "Classic" games upon release of new and inferior versions by Bethesda.
However at least in this instance the games are still in my library years after.
Of note Steam despite its reputation has done the same with LOTR War In The North and Hentai Loli vs Pedobear (don't ask, it was a gift by a deranged friend I swear ;))