There is no factual premise to those arguments, that is the point. There are incorrect assumptions based on false reasoning or just reality denial (in the case of marriage always being heterosexual), which is an unreasonable basis for an argument aka AN UNREASONABLE ARGUMENT.
An unreasonable argument is where the premises do not support the conclusion. We do not question the truth of the premises in deciding whether an argument is reasonable or not.
It'd be fair for you to ask someone to justify why their premises are true. But then that would be a different argument. For those 3, I think you'll find it just about impossible to conclusively disprove those premises. Even if you would never accept them.
That's my point here: you don't have to. 2 reasonable people do not have to disagree. Maybe 2 omniscient people would have to agree or disagree on everything (there could still be value judgments that would probably prevent that even then). But for us, certainly not.
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Congratulations to SuperNiceDog, Guru Winner, who was smart enough to pick
your 7 time champion, Link.