Because 99% of it is better than mine. It's hard to perfect your game when it's a part time hobby with limited equipment, especially compared to pros who spent years/decades studying, experimenting, etc..
I cook, but I still go to restaurants (chefs are better cooks than me) I work on my car but sometimes I take it to a mechanic, etc...
Actually that brings me to my contrarian opinion, almost all my homebrew friends have said their beer is better than pro beer, and I've seen that alot here. But it's not. Sometimes people make really good ones, and obviously I haven't tried people's on this forum, but I doubt it's better. Generally professionals do things better than amateur hobbyists. Sorry but that's just the way it goes.