Anti-authoritarian "leftists" are liberals that recognise that liberalism is bad but have not fully committed to the idea of replacing it. They wear the aesthetics of leftism because it makes them feel like they're not bad human beings but because they have not fully committed to replacing it their instincts are still to support and reinforce the status quo.
They are liberals that feel guilty. It is necessary to challenge them for not fully committing to moving on from liberalism. They must not be allowed to feel absolved of guilt just by wearing leftism aesthetically, they must be pushed into remaining guilty in order to convert further and fully commit to the left.
Only by being challenged and made to see that they are still liberals will they make the effort to fully move on. They re-label themselves to remove that guilt and must not be allowed or else that will be the furthest they progress leftwards.