starry-dota 2 has a pretty shitty pub community for many people, it's still a huge game
You're comparing apples to oranges. Dota 2 is the successor to an already widely popular title and it's being actively supported by Valve. That game had a devout community following before it even hit the alpha stages. A lot of Dota 2 players probably played Dota so they aren't exactly newbies to the game. TF2 is its own beast though. Going competitive is probably an extremely daunting goal to a newbie.
Besides that, TF2 just isn't as well respected as Dota 2, or most competitive PC games in general. To Valve, TF2 is a cash cow. To most PC gamers, TF2 is a F2P casual game. To most gamers in general, TF2 is a crappy kiddie game. This just means the community needs to treat each other well to ensure that this competitive scene doesn't die out due to lack of support, sponsors, and coverage.
Also why bump this topic :x