I don't think Alec belongs with Max (because I'm a total Max / Logan shipper), but I like him.
I think that you're right - that at least a part of the reason Max disliked him so much at first was because he reminded her of who she used to be. Also, on a purely physical level, he reminded her of Ben, the brother she was forced to kill. So on a couple of levels he made her think of things she didn't like to think about. Despite this, they eventually developped a family bond - not a sibling bond, really, I think to Max, Alec was like a cousin with a knack for knowing exactly how to annoy her.
I have seen the animosity toward Alec, and I think it's a bit much, but then, I've also seen animosity towards Logan and even Max.
Personally I like the Alec / Asha pairing, which seems to be unpopular in the fandom.