>>280800992I think he's a shitposter and the world would probably be better if he was sterilized because he sounds brown, BUT if I was to attempt to argue his point from a sincere standpoint:
Mushoku Tensei was one of the forerunners of modern isekai stories, even if the anime adaptation came much later. So by the time most people saw it, they likely already saw many other anime that copied it or attempted to build upon its foundation, so lacking the proper chronology it would seem "generic" to them.