I agree that’s a fair question for a court to determine. And the Supreme Court seems to agree in that they held in 2023 that a threatener’s subjective intent only has to be proven to be reckless (i.e. they knew or should have known their words could result in injury), though they seem split on whether that’s the right standard for true-threat doctrine cases in this Counterman v. Colorado case:
So while I agree a court could find this individual’s reckless intent made his statement a true threat and therefore not protected by the First Amendment, I think it’s more likely they find it was protected political hyperbole, like some politically charged rap lyrics, for instance.
But I disagree that this individual necessarily doesn’t care about mandated vaccines. In fact he seems to feel quite strongly about it. That people like MTG have spoon fed him lies about vaccines and encouraged violence as a solution, that’s where I think the greater criminal intent lies. YMMV