As far as the "computers where not meant for games", damn dude, the first games ever where created on hardware that WASN'T supposed to play games! It was just computer scientists bored, playing around with stuff, thinking "hey, wouldn't it be great if instead we used this thingy to count how much electricity passes through those cables we used it to play tennis virtually, bro?"! Learn your history, youngsters!
And WHY shouldn't computers have games? If you couldn't play Civilization on your computer, would it be as fun on a console? Maniac Mansion? Day of the Tentacle? Even FPS's are better to control with a keyboard and mouse than with twin sticks - don't take my word on it, ask the companies creating them why they don't add cross-play most of the time between consoles and PCs ("it would be bad for the console gamers - mice have more accuracy and thus PC gamers would be better at aiming").
Games like Assassin's Creed, on the other hand, are better with a joypad, and more fun to play in your living room, maybe with friends, than alone in front of a PC monitor.
If you actually think about it, the question in the end isn't about the platform as a platform, but about the controller you use and where you play the game: alone on your PC or with others on your TV. Would you mind if instead of a PlayStation or Xbox you had a PC under your TV, in a same-sized box, playing the same games, but with a controller? (Yeah, I know, "hello Steam Machines"). Would it feel wrong if you played a strategy game on your PS4, but sitting on your desk, on a normal monitor, with mouse and keyboard?
As Sony themselves had correctly said when first "revealing" the PS4 (actually only its joypad), "the box doesn't matter. The experience is all that matters".