I don't believe that he and his wife have stopped loving their daughter. They have set Godly standards and she has defied them. She's an adult. There's no reason why she should be living off Daddy and Mommy.
Sure. Not speaking to her? Throwing her out of the house? Cut her off financially? That just screams love to me.
I think it's a case-by-case thing; I've had four different people I love "come out" to me and I haven't dumped any of them, but only one is in contact with me now. At least two of the three who drifted off are under the delusion that you can't really love someone unless you endorse their lifestyle as perfectly fine in all respects. I, meanwhile, believe love is about accepting people despite their flaws, not pretending they don't exist. (Notice that their "Love means endorsement" doesn't go in my direction; they have no endorsement for my belief in the Bible and Christian orthodoxy.) The 1 left out of the four accepts me despite the "flaw" of going to Alan Keyes rallies and supporting the gay marriage ban, and I return the acceptance despite issues that aren't terribly comfortable.
That said, however, there is no reason for any parents to keep paying tuition for kids who reject everything they stand for. If she was a heterosexual slut or declared herself to be an atheist or communist, her parents should have cut her off as well.