That's not a mental illness that's him just being a jerk. He did make a legitimate point. You didn't really know him, You only knew what he allowed you to know. Which is true of anyone when they first meet someone new.
In the future don't invest so much thought into a potential date. If you start talking to someone, Just chit chat, If that chatting doesn't result in a date soon , as in like a week 2 at most... then stop chatting and move on. You can only be lead on if "you" allow it.
I'm sorry he hurt you, just use this as a learning tool..