That was the creepest scariest scene in the entire movie, him blackmailing her. Sad those things really happen.

He either didnt understand what he was doing or didnt care. Lou is good at reciting facts he memorized off the internet, but he doesnt truly understand a lot of things and hes pretty horrible at social interactions.

She did object, however, she didn't want to risk losing her career.

He knew but he also decided that it was what he needed to do to get what he wanted. Nina could have had him thrown out for his advances but she was unwilling to sacrifice losing his reports. In the end they both got what they really wanted. You gotta remember not all men and woman object to sexual harassment, only when they object is something done about it. Did we observe Nina objecting?
Lou