I think you've got a good understanding of the anarchist position.

I think there's something else going on, which is a bit of a semantic mix up. Anarchists often support something leninists would recognize as a vanguard: an organization of concious members of the working class leading the proletariat to seize their farms and factories.

The debate isn't over whether or not there should be a vanguard, but what form the vanguard should take, with anarchists being insistent on vanguardist organizations prefiguring communist relations.