Most Helpful Guy
He hasn't given up hope yet. Ask yourself why it is that he is so hung up on you. Instead of treating him like garbage, here are some good alternatives:
1. Self-deprecation: "I would be a terrible fit for you because..."
1. a. Self-indictment: "The last time a guy like you tried to get with me, I wound up...[insert random true story here that makes you sound like a bad luck charm of the worst order]. I think you deserve better."
2. Referral: "I know someone who'd be into you a lot more. And they can help you with [xyz attribute of his] way better than I'd ever be able to."
3. Relationship switcheroo: Change the terms of the relationship to one of you mentoring him in the ways of finding love with some other woman. Get him comfortable with taking your advice over another, instead of trying to woo you. Just realize this still requires you to commit to a role. And if you don't follow through, he'll see you as a scumbag with no integrity.
4. Political backstabbing: If you have differing political views from his, say something offhandedly that he'd get offended by. He'll see you as an adversary to debate or avoid, not a date to pursue. Just make sure you don't need him for anything in the future, as that bridge will have been nuked to ash and cinders.
5. Control freak: Lay out a list of arbitrary rules for dating that are so insulting, demeaning, and impossible, that he flips you the bird and leaves. Just beware if he sees you not hold another man to those same bullsh*t standards, he'll think you're a bitch and might hate you forever.
Things to NEVER do:
1. Attack his ego directly.
2. File false reports. That is a declaration of war that you will regret.
3. Give beat-around-the-bush excuses in vague terms. This creates a puzzle that he'll want to to solve, making more problems for you.
4. Pretend to date him, then (figuratively) stuff him in the closet and slowly bleed him dry emotionally. He will thirst for revenge. Stupid move.
5. Insult is family. Just don't.
Most Helpful Girl
He probably thinks you're going to change your mind.
Anyway, ignore him. He will eventually stop.