Why is Being a Tank/Support Player consider more Self-Righteous than Dps

I chose to play tank first. After that I played support. Now I wanna play dps. The thing is, although there is a 54% chance randomly picking a dps character THIS assumption of 54% main dps is a flaw in itself because you don’t have pick randomly IN A GAME. Like I said I play two roles and quite good as well. I can choose both. As a player in a match I could choose dps in order to learn dps heroes and how they work and function ( although I am a tank main). Why can’t a dps main do that too? For me playing tank and support is not a self sacrifice but I wanna know HOW DPS WORKS ABD TO COUNTER THEM. Is that logical? I think so. I think your description is corrupted because 2-2-2 gives me a opportunity to play dps and having a functional team rather than a dps main not switching of to another role (because he doesn’t want to or he can’t player other roles). So, that is my thought on that…