Sounds to me like your normal stable family should have raised someone more mature and reasonable, and less judgemental. Compromise. Spend some time with each family, or if that isn't possible, alternate each Christmas. Or figure out something else, but in any case, work something out that you can both agree to and be reasonably happy with. Asserting that she should choose to be with your family instead of hers because yours is better, unless hers is abusive or something, is childish and selfish. It's not a healthy approach at all.

Look, dude, as someone from a Spicy Family, that's not how it works. Even when your family are irredeemable bastards--and I'm speaking from the time when my dad openly said, in the middle of a grocery store, that queer marriage would make a mockery of his and my mom's--you still want to spend holidays with them because blood ties are a bitch like that. Yes, your family is healthier. No, that doesn't override the years of loving people in the worst possible way. You're gonna have to split your holidays like the rest of us, because you love her, and that means you have to let her love other people.

She can spend her christmas wherever the fck she wants, no?

It sttinks when you cannot be with the one you love on a holiday. One thing to keep in mind is an old saying, "A daughter is a daughter for life. A son is a son till he takes a wife." The general premise, regardless of gender is that, women maintain a close relationship with their family (familiarity/comfort/security) even if they are not truly keeping her best interests in mind. There are many nature Vs. Nurture arguments and theories. A much longer conversation for another day. You can work on alternating holidays/years between families when that time comes.