Notice the similarities between Antifa and the KKK. Both wear masks and when in public hide their identities. Both operate in areas where the elected officials law enforcement and the local Courts are sympathetic. Both do violence. Both draw mostly male members from all levels of society.
The best way to destroy Antifa is the same way the KKK was destroyed. Identify openly and publicize the members and their supporters. Prosecute them in Federal court for civil rights violations and other crimes. Sue them personally for damages.
“...Prosecute them in Federal court...”
You are assuming we actually have a system that does that sort of thing. The FBI word proccessor experts won’t get anywhere near it unless the locals do the grunt work first.
We need a right wing SPLC to empty their coffers and jail their membership/donors.