There’s no defending the USSR or ML, so I’m not going to bite and engage in an argument designed to downplay the evils of it.

Lol, yes there is, and it is a very simple argument:

1. A transitional state moving towards communism is less violent than a capitalist state.

2. All large anarchist attempts at governing were basically the same as the USSR under war socialism(Catalonia, which started much more industrialized, and lost, because of, among other things, anarchist organizational failure) or worse (free state of Ukraine, which led to a wave of pogroms because they refused to suppress reactionary elements))