That's true. Max had to stay away from Muggl...errr, humans, on principle, but he did have human loving parents so he let someone in by definition. Even if he never healed Liz, he'd still have someone he loved he'd have to leave behind (and of course, even prior to talking to Liz he was in love with her). Ditto for Isabel.

Michael's only people he cared about were the fellow freaks. He had no loving parents or hidden love for a human girl or any of that baggage.

he pulls a Harry Potter by trying to keep her safe by cutting her out

If anyone did that to me, I'd be torn between "awwww" of "he loves me so much and is so caring" and the strong desire to hit him with something exceedingly hard because it's not his choice.