WHY ALL THE CHEESE?

I been playing games at my local GW and it seems everyone is obsessed with cheese. Anything i use and win with must be cheese and god help you if you want to take more than one of the same thing in your army. I see much cheesier lists everytime i look on the net but If i take something like an example of Fear of the darkness librarian i get ripped into about it by 3 or 4 guys and the redshirts as i play with someone. There not even in the game. The libby walked into battle in a termie squad. it didn't even ds or pod into battle.

Another guy there got the same thing for having 2 wraithlord in his army and that was from a gw staff guy who has 3 wraithlords and no wraithguards in his iyanden army.

so whats with all the cheese guys? why can't i take what i want without all the comments and people saying maybe we shouldn't let him play in the store?