Threads turn toxic because people treat eachother like the enemy. We constantly fail to respect the other person when he or she has a different point of view.
If your way of life is changed in a way you disagree with, e.g. forced vaccine or Use of Corona passport, then discussion can get heated and the respect is lost.
In this article i find it unprofessional to flag it, i would sincerely hope that Hacker News is better than that.
It should be the merit of the article and not politics that decide if something gets flagged or not.