
He’s so fucken stupid I love it.. also someone tell these mangaka that bisexuality is a thing lol

That's not how sexuality works tho. He couldn't get hard because of psychological reasons. He was in love already, but since this was a new experience, he didn't quite yet understand what he was feeling. He definitely still finds women attractive. It's not like turning off a switch, you don't just suddenly stop being attracted to a gender just because you discover you also like another.
Why does the professor gotta be so damn hot yet so damn creepy