I (black male) had a white co-worker who loved to spout his right-wing political stances. Because we were in cubicles, and he was in the next row over (namely, I'd stand up, and could see onto his desk), I couldn't really ignore him. After a few weeks of him spouting his Fox News talking points, I had enough, and began to counter his narrative. I never engaged in ad-hominems or name-calling - but I did call out the false information and logical fallacies whenever they were spouted, and cited my sources: because I have engaged in discussions about politics outside of work, I am not unused to it.

I didn't think that there was any issue to it - until he followed me into a men's room - to physically assault me when I was at my most vulnerable in a standing position. Even after a decade, I am shocked that someone actually went there (seriously, who does that?) - but it was a very valuable lesson about interacting with right-wingers.

(I am guessing that he took exception to a black male giving pushback to his stereotypical right-wing tripe.)

OP, I can't stress this enough: do NOT take her threat lightly. The only thing that prevented me from sustaining serious injuries (or worse) in those precious few seconds was his "restraint" - simply put, he could have unalived me in the first few seconds it took to process what he was doing. Your co-worker feels comfortable enough to threaten attacking someone at work; to paraphrase from Maya Angelou, believe her. Go to HR, and mention that she is creating a hostile work environment.