Interesting. I would like to meet this person. I find it very helpful to surround myself with people that have a different way of seeing the world.
No, no no no no. No you would not. Not unless you mean it like "I'd like to meet a serial killer, just for the experience." Maybe it'd be interesting to get their point of view, sure, but you are far better off without them in your life. And certainly without having any form of relationship with them.
One of the main reasons this guy wrote this letter was probably self-aggrandization. The very fact that you find him more interesting is exactly what he wanted. That's not inherently a bad thing.
What's inherently a bad thing is that when human remorse and guilt have been genetically disabled, those people will do things to you which are fucked up. I have experienced the blunt, raw force of their emotional carpet bombing firsthand from a certain family member.
Everyone needs to remember that these people are hardwired to be deliberately manipulative, because they feel good only when you're giving them attention. Then they feel good only when you're doing things they've conned you into believing you want to do; sometimes things you'll feel shitty about for the rest of your life, once you snap out of it and realize you've been a puppet.