We need to build a "big tent" to defeat fascism. Purity testing and divisive language make our tent smaller and lower our chance of success. It IS important to take more direct action, to not be a slacktivist, but we have to encourage people to do it, not try to shame them into it.
I think the core point is to not judge without info and not cross the line into being a dick to people who are on your side but that you view as "not doing enough".