I can only imagine: some sort of insanity as at hand. Maybe the father has fought gay urges his whole life (who doesn't like drag shows and disco balls...)
Or maybe the parents are just not that intelligent. The hate engendering the words you mention are guttural. It is not a human reaction, but animalistic.
Sadly, I think many of us have these animalistic flaws, in various arenas. For me it is gluttony for women, wine and pizza.
Maybe the parable here is that each of us is flawed. And while we lack the ability to change others, we are wholesale our own masters. Maybe this is a good time to reflect on ourselves and become better people, since the family mentioned does not have that option right now.
That said, I will not be giving up wine, women or pizza.