It is a bit strange to see players type "I play Support or Tank Plz". Competitive isn't so bad as players here might make you believe. I play Flanker or Damage more because i don't want 2 Tanks or Supports in my team in certain maps or against certain team comps(Drogoz,Bombking) when its too hard to win.
Maybe i am just lucky so far. But Tanks & Supports are very common in competitive. In casual barely anyone plays them.