You know some people just want to beat a game? And a large majority never seem to beat any games? I'm just on the other side, I like to squeeze every ounce of game out of the game. It's not that I want a platinum trophy, is that a spent money on the game, like the game, and getting the Platinum feels like mastering it. I'll do the same thing with stupid flash games and Android games, getting 3 stars on every level even if I don't really like the game.
It's not really an issue until you add in terribly designed trophies that don't respect the player. I have no issue with beating a game on a high difficulty level, I find most games too easy anyway. But in a single playthrough? Silly. Or difficulty levels don't stack so you have to play a game 10 times? Awful. As long as trophies are created in a thoughtful manner I think they're a great idea. Unfortunately once you get in the habit of getting platinum's you'll run into games where all of a sudden you realize there's one grindy trophy between you and the plat.
I think the issue is just avoiding a game all together because of a trophy. Thats holding a bit too much influence over someone.