This game emphasises a fast-paced, fun over realism style. CS is far more slow paced, and so they can use fancy skins, but for UrT, the gameplay is so fast that trying to distinguish between similar skins is going to slow the game down; therefore we use bright, easily recognisable skins.
Bleh, I personally don't think the CS:S skins look as realistic as the URT ones. I watched a CS:S video and was quickly wishing for URT graphics back.
How do you guys expect anyone to be able to focus when
that is staring at them?

~Cody