[a_puppy]

I agree if a man sleeps with a consenting woman but later chooses not to enter a romantic relationship even though she wants to, that's not evil by itself. Some people would say that he's "using her for sex" or a "womanizer" or whatever, as if sex includes an implicit promise to enter a relationship; I would disagree.

But that's not what's going on in the case of Eido Shimano. He was a teacher sleeping with his students, which is generally considered unethical. He appears to have led his sexual partners to believe that they were in a monogamous relationship, then cheated on them. He repeatedly harassed a woman who refused his advances. And at least one woman accused him of groping her, which is just plain illegal. I think it's fair to call that behavior "evil" and "exploitative", and I don't see anything weird about the article framing it that way.