I've never been excited about sports, unless I was playing, and not always then. At the SuperBowl parties I've been to I spent more time in the kitchen with the snacks and good conversation than in front of the TVs. And what I don't care about I'm tempted to deprecate.
But we're not overburdened with things that bond us.
The Cubs aren't just Chicago, they're regional--Oak Park-ians can call them "our team" as easily as 4'th ward-ians. It may well be the only thing that links them--a trivial thing, but better than nothing.
The "laundry" isn't just a team symbol but a symbol of "membership in my region," and it's an American sort of ideal that you can change regional membership.
I'll try not to disdain "rooting for laundry."
And cat videos--anything benign that draws the disparate tribes together is beneficial. They won't cure our problems, but despising the little things is worse.