Why is this person being so disrespectful towards me?

Maybe is the type of site you're in, you did the right thing, if he continues just cut him off. But males do feel attracted just by physical appearance. 

Tinder for ONS and hook up

So yeah he will keep lewd you because he wanna have sex with you 

There are dating sites that cater to quick hookup and focus a lot on sex and there are those that market themselves more as a place to facilitate relationships. It could just be that you're on a site known to be more one-night-stand than love-of-your-life. 

He can be physically attracted to you at first sight. He is only looking to bang you. Like someone mentioned people going on dating sites only look for casual sex. Some guys are idiots and don't know when to stop when you tell them something. If you don't like it just block him. He will hopefully take the hint. 

For your own sake, stop talking to him.. look at what he has told you about himself already - he insists on talking about something you told him not to - this not only shows that he isn't listening to you, but also, that he doesn't respect you, or even care what you want. He's also made it pretty clear that it is not YOU that he wants, it's just sex with you.. he'll even risk losing your friendship/companionship if he thinks that you might just give him what he wants - which is sex.. 

A lot of people use dating sites for casual sex, sounds like you’ve found one of them. Sorry but it doesn’t look like he’s interested in a relationship and just trying to sleep with you or get nudes. 

Don't think he was trying to be disrespectful, he was obviously only looking for sex. You can be attracted to people you've never met before though, like sexual attraction is a thing.

Just avoid the pervert. Because that's what he is.