There seems to be a general divide between men and women whether men abandon their kids or the moms alienate the father.

I'd like to focus on the alienation part.

I have one friend who has spent upwards of 50k on legal battles because his ex wife keeps moving and not letting him see his daughter.

She keeps getting slaps on the wrist by the legal system (if that), is good for a month or two then alienates him again.

Every time I talk to him, he's just so disheartened by the lack of justice and he really misses his daughter.

Aside from a dangerous environment for the kid, why do moms alienate good fathers who want to be a part of their kids lives?