they *were* anti-Communist, but you have to bear in mind thay "Communism" to them referred to a very narrow political movement at the time, and it was an **entirely** Leninist one.  Other communists rarely adopt the capital-C Communist label since MLs (or MLMs) always get to it first.    In any case though, he's explained that he doesn't go after Communists for the same reason he doesn't go after Monarchists.  They're completely irrelevant.