"We" could all agree to stop Hitlerizing each other, but for one problem. The demonization is very imbalanced. It's much more mainstream among Dems and Progs than among Rs and conservatives. I see and hear Dems/Progs calling people they disagree with "Hitler", "Nazi", "Fascist", "Racist", "Misogynist", "Homophobe", "Islamophobe", and more routinely. Rs/Conservatives use labels like "Commie" or "Socialist" far less often.
This can be seen easily by browsing TBR or Conservative Cave and then by browsing Democratic Underground.