We have seen people with signs dooming gays to hell. We, as a nation, didn't kill those people from Westboro Baptist Church.
We didn't pull guns on them.
Our culture, despite the relentless press about WBC, consistently and repeatedly opposed them via our country's legitimate methods, by counter protests, by barriers of people to volunteer to show up to shield grieving families, soldiers' families, from seeing all that free speech.
Our democracy worked. The protesters, representing the most extreme minority in our vast land, even smaller than the gay population, were allowed to be obnoxiously visible and make their point, enjoying freedom probably far beyond the vision of the writers of our Constitution. And the same rights were afforded at the Lincoln Memorial recently when Black supremacists made horrible racist jibes and jeers in a public gathering, just as obnoxiously free to protest.
People were not condoned to approach them and threaten them by force of arms.
And to your point, this man is in jail and would appear to identify as white male, so he apparently isn't free for his actions, so there's that.
"Being bothered" is not the question at all. It's a question of making threats, in this case, with force of arms. And all of that before you address the question of whether MAGA can even be legitimately be considered to be derogatory in any way. This was a Tennessean menacing a pair of Kentuckians. Hardly an immigrant confrontation. However, if the gun toter is possibly transgender, then perhaps he represents a threatened group by interpretation.
And by no means conclusive, this web page (for an article's contributor), suggests that James may indeed be trans, so might in fact perceive himself as threatened by the movement the hats represent:
https://www.utdailybeacon.com/users/profile/jphill92/
But, it would also make him an activist on the left.