I think some of this . . . need for enthusiastically supporting some team or party or whatever is left over from when there were more little tribal wars. We're probably kind of wired for weird, largely baseless passionate loyalty and we can't really just go out with a bunch of friends and raid the neighboring village anymore. This is what we're left with.
I consider it better because being widowed and/or raped and/or enslaved multiple times in my lifetime is not appealing to me. Then again, it might not be multiple times -- there was always dying in childbirth to cut short one's suffering.