I agree that he should use his knowledge to prevent them getting abused, but that doesn't mean preventing them from having sex. If the girls like it, just let them be. He should have enough knowledge to know when the relationship goes to abuse. That's when he should put a stop to it.
If he was just seducing them into being Sex Friends then maybe you'd have a point but he's intentionally causing harm both to the girls and others (he loves cuckolding). Also it seems that torture and drugs (for tag:mind break, I assume) are involved. Also once they're Magic Dick junkies they may not listen to anything he tries to do to keep them from being abused.
Took me till now to find out this is the same author as Youkoso Isekai e, dewa Shinde Kudasai. hopefully he can actually choose whether he wants to do plot or just make an H with this one.
Took me till now to find out this is the same author as Youkoso Isekai e, dewa Shinde Kudasai. hopefully he can actually choose whether he wants to do plot or just make an H with this one.