Earlier quoted context omitted.
The pizza on that page looks extremely greasy and - most importantly - burned! Hope it's not representative of New Haven pizza in general.
I have eaten those style of pizza. They are tasty. Not everything must be Neapolitan to be edible. I think it may depends on local ingredients - since Italy has amazing ones it is just a matter of putting simple toppings with minimal heat processing not to fuck them up and serve. If there were no good local substitutes you have to pump up the grease and toast the ingredients a bit more to make it flavorful enough.
Given that these places served a lot of immigrants when they opened, I also wouldn't be surprised if it helped having a sturdier pizza that you could take to work with you.