TFC got killed by the huge flood of 8 year olds with no idea what tactics are. TF2 was an attempt to make it so that the little 8 year olds that ruind TFC couldent kill the new source version. everyone just hates it because its actualy hard to be good at.
Same goes for CS, in the first couple of years it was on steam it was actualy more playable than the WON version of the time, but again, way too many under aged kids got to play it and destroyed the community. Parents just don't look at the 17+ logo plastered on the damn box.
And it has extended to the mods on both the goldsrc and source engines, half the games I used to play are flooded with so many kids who have admin powers who realy shoulden't, that I get banned just for trying to play tacticaly. The only mods that are safe are the ones that are complicated to play, and the little kids say "this sucks, CS is better, its the PAWNZORZ!"
Sort of how LFS is getting, its becomeing realistic enough that you actualy have to know how to drive in order to play.
You can't blame steam for screwing up the gameplay, its the people who play it that make it bad.