Because ANTIFA is composed entirely of democrats, many of them in leadership positions across the country. ANTIFA is the newest enforcement agency of the DP, same as the KKK in the past. They are the Brown Shirts in their black uniforms, sort of like BDUs.
“The Sturmabteilung (German: [ˈʃtʊʁmʔapˌtaɪlʊŋ] (listen); SA; literally “Storm Detachment”) was the original paramilitary wing of the Nazi Party. It played a significant role in Adolf Hitler’s rise to power in the 1920s and 1930s. Its primary purposes were providing protection for Nazi rallies and assemblies, disrupting the meetings of opposing parties, fighting against the paramilitary units of the opposing parties, especially the Roter Frontkämpferbund of the Communist Party of Germany (KPD) and the Reichsbanner Schwarz-Rot-Gold of the Social Democratic Party of Germany (SPD), and intimidating Romani, trade unionists, and especially Jews.
“The SA were colloquially called Brownshirts (Braunhemden) because of the colour of their uniform’s shirts, similar to Benito Mussolini’s blackshirts. The official uniform of the SA was the brown shirt with a brown tie. The color came about because a large shipment of Lettow-shirts, originally intended for the German colonial troops in Germany’s former East Africa colony, was purchased in 1921 by Gerhard Roßbach for use by his Freikorps paramilitary unit. They were later used for his Schill Youth organization in Salzburg, and in 1924 were adopted by the Schill Youth in Germany. The “Schill Sportversand” then became the main supplier for the SA brown shirts.”
https://en.wikipedia.org/wiki/Sturmabteilung