The problem is honor. Assholes like to play video games. It's one of there many hobbies. These assholes like to play the latest and greatest games out there. These assholes also enjoy winning. Most people do. The problem occurs when they'll do anything to win. For example, In CoD WaW, rifle grenades were used to survive. They had a word for people who didn't use them: dead.
As the game progressed though, people stopped playing. They were bored winning here, they needed a new frontier. Leaving the scarce few to battle amidst the multiplayer ghost town. Something within them changed when they didn't need to rifle grenade to make a kill that round. They stopped. Now as the asshole breed is falling off of the MW2 wagon, they fall back to games they remember. When the assholes dusted off there rifle grenades, they were scorned by the community. They lived in peace while the assholes were gone, earning kills with their guns, not their weapons a secondary to their kill streaks.
There is a distinct difference between the two games now. When a player is killed by RGs in MW2, they complain about it and pull out theirs to handle the situation. In WaW, the player doesn't pull his out. He makes it a point to kick the user's ass using an even lousier gun than before to be able to mock the RGer for sucking.
Lesson? Step back from the arms race, and have some goddamned fun for a change.