Or, alternatively, because they're on the computer.
The medium really doesn't make that much difference. It's perfectly possible to make a really good game on both platforms, and ya know, it's been proven over and over again. Mouse-and-keyboard is not the Ultimate Control System - you might be better with it, but there are people who are better without it also. And there are games that just plain wouldn't work with it. In Blinx I *needed* a fully analog "look" and a fully analog "walk". Guess what, I had two analog sticks. (Handy how that works, isn't it?) That game couldn't have existed in that form on the PC.
There's also the fact that gamers' expectations are wildly different on both platforms. PC gamers expect to be able to save anywhere, no matter what they're doing. (This, incidentally, makes me feel that most PC gamers are wimps.) Console gamers are quite willing to live with save restrictions - after all, only the XBox has gotten to the point where arbitrary save positions are even possible. Console gamers don't want to micromanage, PC gamers do. I personally rather like both console and computer - I just finished Unreal II, and now I'm going to plug my way through FF9 while I slowly slog through Gun Valkyrie. They're all good games (well . . . okay games, at least) and really, I don't care what platform they're on.
But here's the thing that bugs me. Computer and console are capable of nearly the same games. There are a few restrictions - lack of keyboard on the console's side, lack of standardization on the computer's side, more RAM on the computer but only one player per system (99% of the time - yes, there are exceptions, but unless you're running an emulator, I haven't seen anyone do two-player single-screen for the last few years.)
So why do people take a single feature of a single game - unlimited ammo in Gun Valkyrie - and try to turn that into an insult on the entire genre?
Why do people say "Halo's control scheme sucks" when it works just *fine* once you get used to it? Just like mouse-and-keyboard does, only you've forgotten because you've been used to it for years? (And trust me, you'll get used to Halo's too, since most console shooters are using something similar if not identical.)
I'm sure there are many equally groundless complaints about the computer (including, no doubt, many people talking about how unusable mouse-and-keyboard is), but I don't hear them often. Still. It's like refusing to watch More because "claymation is stupid", or hating certain artists because you don't like oil paint, or avoiding Cowboy Bebop because anime is all porn and violence!
People do that.
. . . bad example.