Have you considered listening to the pretty extensive explanations they’ve given in this comments section as to why?
I was just entertaining a notion as I lack the skills to do an analysis like you did.
As for reading the other comments here, I have read them now, and they are interesting, but when I first commented, there were no other comments here and the post stood at -3.
Not how it works. Gestures, like words, have a meaning. Even in the USA, saying certain words in certain ways can get you arrested; harassment, threats, etc. This gesture is meant to convey threat and to harass religious and racial minorities. There is no other reason to make the gesture.