Antifa, indeed, opposes the individuals and organizations which threaten liberty, justice and equality.  Their very title "antifac" means "anti-fascist".  Regrettably, their tactics are, in themselves, threats to the very concepts they profess to be protecting.  IMO, it's impossible to justify violence and censorship in the name of freedom and equality.  The only exception I can imagine is a genuine rebellion/revolution against a dictatorship.  Even then things can work out well.....or they can work out very badly.  Examples:  The American Revolution, which most folks would agree worked out well.  on the flip-side: the Cuban Revolution against the tyrannical Betista regime, which led to a government arguably just as dictatorial.  

Today, IMO, antifa is an example of "The ends DO NOT justify the means." following is a definition: Gary Crum