You're not wrong about the north end! But Boston has a particularly bad rap when it comes to pizza. Probably mostly from New Yorkers who don't realize you pretty much have to go to the north end to get the good stuff, unless you already know where to go. And bad pizza isn't in short supply if you don't know where to go.

I once had an old lady come up to me and, completely unprompted, give me a lecture on the difference between the German words "kein" and "keine" as if I had mistakenly used the latter instead of the former. She was in a heated argument with someone else at the bus stop but she saw me approaching and ambushed me with that lecture as soon as I got there.
She did not stop arguing with strangers the entire time I was within earshot of her, which was quite a while.

Not to defend Chicago style pizza but Boston doesn't really have much of a leg to stand on there