"Anti-antifa" is a common dogwhistle for the promotion of fascism. Antifa stands for "Anti-fascist", implicating the double negative suffix "anti-antifa" as "fascist".
Antifa is also a loosely used term associated with anti-fascist and sometimes broader anti-racist groups. As most antifascist groups and activists are politically leftist, "anti-antifa" branding is sometimes marketed as anti-leftist, rather than pro-fascist. This strategy has been used historically to push neofascist movements to mainstream appeal, such as the explicitly neo-Nazi Rock Against Communism movement that positioned white power rock music as though it was primarily anti-communist rather than white supremacist.