it wasn't ok to be hurt by that? I find that bizarre.
Who said that then Change? No-one can tell you what it is or is not OK to be hurt by.
I always tell people when I don't want to see them again, if they message me to say they do (or if it's been a few dates and I've decided it's not working). If they don't, I don't initiate a conversation. If I do want to see them again I might initiate a conversation if they didn't.
The point is, there are twats in RL and twats online. You maybe don't meet so many in RL as your circle is small and people who are know by you through other people have the peer pressure of behaving properly. Online, they don't and the circle is far far wider, plus it's self-selected to a great extent. So, it's great that you get to see how much of a twat they are quite quickly.
But, you can't change their behaviour, you can only change your response to it. If you accept it happens and move on, you'll find it a lot less frustrating overall.