It's just a very convenient way to dismiss an entire library of games, so they can "ignore" the system with said library.
Even the opposite it's true, though. I see many posters saying "I bought a WiiU at launch for Nintendo games", as if "Nintendo" was their favorite genre. Both fans and haters treat Nintendo as a indistinct block, or at least they talk about it that way. I also see people saying "I got a PS4 for Sony exclusives", without mentioning specific games.