Why Japanese are obsessed with slave theme in Web Novels

Hello i read some WN novels and must say all those fantasy novels (with reincarnation) have one thing common the MC buy/own slaves as normal thing, although most of them are reincarnated from modern world, the question i often ask myself why they aren't fight against that but go along and many times not only own slaves but also sexually use them. For me as european is something wrong with slavery (Probably the last slaves in europe were about 10 century so it something that we learn from milk of mother like we said in my country). So must ask if in modern Japan is there other view for slavery since all MC in WN don't anything to improve status of slaves or abolish slavery. They mainly use and own slaves on their own as normal thing in the world. I think also is possible that slaves are dreams of "otakus" in Japan, which is why is hard to find any normal thinking MC in web novels since most of them are writted by "otaku" for "otakus".



ps. As someone who believe that freedom is something basic for human i usually abandon any web novels which has slaves as one of theme of novel.

Why Japanese are obsessed with slave theme in Web Novels