it's pointless arguing with people like this.
My opinion is that people who argue solely based on emotion, and not logic actually probably do have a mental disorder, and they love gathering up validation from other people who think similarly (also with mental disorders). I had an exgf with BPD, and this type of stuff is exactly the same type of mental gymnastics. Only once in a while, she'd come up for air, and admit she's wrong and nothing of what she says is logical, before lapsing back into insanity. And as you're discovering, if you cross these types of people, they will go through any length to watch you burn. She'd claim you threatened her, and would be glad to see your guns taken away and you left to rot in jail for no reason. She'd do this and not even feel guilty. This type of people have no conscience or morals. For your own good, you should stay away and not engage in arguments with them.
Also note that the type of people who is attracted to and utilize social media the most tend to have some sort of cluster b mental disorder. Example: if someone's instagram page has 99999 selfies, higher chance they're NPD. Long story short, by posting something controversial or political, you're stomping on a nest of crazy people.