This proposal in Meta is flawed and this should be pointed out. It was agreed a while ago that proposals to ban that do not include any evidence should be deleted. The "evidence" here is simply showing that /u/redsteak posts on a certian subreddit (that some people find objectionable), but simply posting on different subreddits is not and has never been grounds for bans here.
Enkara (who is likely doing this out of personal grudge) has not highlighted WHY they should be banned but simply said they should be, but has provided no evidence.
The futurist artists by and large supported fascism as they saw it as something that would revitalize their country and move it into modernity and the future, and many acted as propagandists for fascism with their art and actions, with Marinetti, who started the movement with the Futurist Manifesto, being, himself, a part of the Fascist Party in Italy and attempted to get Mussolini to make futurism the official style of art of Fascist Italy. The art movement itself promoted fascism.
That being said, there was a small minority of futurists who were leftist and antifa, but they were marginalized in the movement, and, in the 1924 Futurist Congress, the anarchists and socialists in attendance left in disgust over the fascist politics within futurism.