Really? Could you point at one of these shell companies?

In the social justice context, "cell" is a better fit than "company". Some are Antifa Ost, Informal Anarchist Federation/International Revolutionary Front, Armed Proletarian Justice, Revolutionary Class Self-Defense, and Rose City Antifa. If Greenpeace had organized like this, their liability would likely be far lower, but so would their organizing effectiveness.

The expected response from both companies and social groups is to deny the affiliation. The overall strategy is transpartisan because it is effective.