I've been told before, "Dex, why do you have so much hate in your heart for baseball teams that aren't the San Diego Padres or their minor league affiliates?" And to them, I say, "It's my way."
This is true for most teams. Other teams actively try to draw the hate forth. For example, observe the following video. I already hate the San Francisco Giants, but then they go and 1. Do karaoke badly. 2. Sing Sweet Caroline Fenway style complete with the "So Good" chant. It's like, Hey, we're the giants and the only thing we got going for us is that we aren't those douchebag Red Sox! But now check it! We gonna rectify that shiz right here!
I know no other explanation for it.