Many people think that marriage is a man/woman thing, as it always has been.
It is a valid opinion and widely held. A large minority.

No-one should be labelled as a homophobe or a bigot for that. It was the status quo within our lifetimes.

Why not just challenge those views and argue against them?
It is because you can't do that, that you all resort to abusive labelling and name calling instead.

And you tell yourselves and each other that it is something noble that you do.
It is not.
It is inadequacy.
He can beat you every time in debate, so you run from it, streaming nasty words over your shoulders as you go.