The absurd idea that one should have “no enemies to the right” is based on the absurd idea that progressives do not police their ranks. Only people with no knowledge of the left could think this. Take Noam Chomsky: by no means the furthest left of leftists but a man who is consistently, extensively and very publically condemned by mainstream Liberals. Why? Image, of course. They have no wish for people to associate them with real or alleged America-haters. But it is also because of something deeper. The left and the right are heterogeneous and doomed to heated competition over which beliefs and goals acquire status and significance. Within the left there have been long-running arguments over US foreign policy and the state of Israel and hawkish Liberals compete with anti-imperialists over whose ideas will define the Democratic Party and left-leaning cultural institutions. Did this stop them from beating the right? No, because – and hear me out on this – people can do more than one thing at a time.
There are qualifications I should add at this point. Internal criticism can become indulgent and introspective. Disavowals can be cowardly and dishonest. But there’s really nothing wrong with hating Nazis.