What is this nonsense? When playing in a club, I always try to psychologically pressure my opponent because it's an element of competition, an element of the fight.

I usually call the person on their mobile and tell them that their apartment is on fire, or I ask a couple of guys in suits, with a clearly visible holster under their jackets, to stand behind me. After all, it's an element of competition, and it's not nonsense at all.
Seriously, if you compare it to chess, during a match, players are allowed to say only two things: adjusting their position and offering a draw. Everything else is considered bad manners, and various provocations are beyond the pale and only happen in children's competitions, and even then, rarely.