@garbados The wikipedia introduction to Antifa actually explains the problem (and the intention of violence) rather wall. Notice the words violence and "militant" as the defining quality of Antifa (which differentiates it from anti-fascism in general):

The Antifa (English: /ænˈtiːfə/ or /ˈæntiˌfɑː/)[1] movement is a conglomeration of autonomous, self-styled anti-fascist militant[2][3][4][5][6] groups in the United States.[7][8][9] The principal feature of antifa groups is their use of direct action,[10] harassing those whom they identify as fascists, racists or right wing extremists.[11] Conflicts are both online and in real life.[11]

They engage in violent protest tactics, which has included property damage and physical violence.[7][12][13][14] They tend to be anti-capitalist[15] and they are predominantly far-left and militant left,[16][10] which includes anarchists, communists and socialists.[17][18][19][20] Their stated focus is on fighting far-right and white supremacist ideologies directly, rather than politically.[10]