No Jew has a right to call another Jew any sort of names. V’Ahavta L’reiacha Komocha. The Chofetz Chayim says that one of the strongest forms of Loshon Hora is to talk about an entire community.
I Daven Sefard. Occasionally I Daven in a Litvisheh Shul that of course Davens Ashkenaz. I Davened there The first 2 nights of Pesach. The Minhag there is not to say Hallel by night. Being that there are a lot of people that Daven Sefard in this Minyan, they implemented, that after Kadish Basra they wait a couple of minutes for those who want to leave and then start Hallel. About 7 people walked out, the rest stayed including the Rov.