Frankly, I'm generally sceptical about online sexual harassment and related issues. "Online" context is different enough from the real world that you can not simply import the definitions change. But I also think it's important to be able to justify that position and give people their day in court, so I would look at what is being said and see if it stands up to scrutiny.
My logic is that the behaviour of the harasser is not the equivalent of a cat-call at the fact that the incident occurs on the Internet.