How are they clearly pushing government funded "gay thing"? The fact you can't even name it correctly shows your probably against it to begin with so let's see how far down the subjective rabbit hole we go with this.
It's okay because it shows that the community supports all walks of life, as
@Johnnypenso just demonstrated. I don't really like having Breast Cancer awareness shoved down my throat at various points of the year, but I understand why people in communities get together over it. I don't care for various other things being blown up either, but yet I accept that others support it and it's their community as much as mine.
Also if it doesn't comply with your religious belief (weak strawman by the way), then you're not driving it. Infringing on someones religion is against the law so...
Also the law is that gay marriage is legal, them showing a vehicle in this way shows that they up hold the legal status of it. That they support the lawfulness of those who are same sex. There is a difference between supporting something and making a political agenda where one shouldn't be and doing something because it is actually an accepted legal norm of society. You've mixed that up here.