I'm pretty sure that if you do a search you'll find plenty of threads praising the game as well. But here's the thing, it's boring talking about the good things in a game, nothing constructive comes out of it and it is, in all truth, nothing but a big fanboy love-in. Talking about what GT5 doesn't have and doesn't do well is interesting because people have different ideas about what they want in the game and it's spawns a variety of views and opinions. The threads you're talking about go along the lines of:
OP: "I love GT5 it's amazing"
Comment 1: "yeah I love this game too"
Comment 2: "Me too, let's give PD some love"
So forth and so on.....
Boring.