Ok, so if you ever get into a kerfuffle with an anarkiddy about state socialism or “tankies”, then use this statement:
Anarchism is unfeasible because the lack of a state makes a nation vulnerable because it doesn’t have a centralized military to protect itself. Marx’s “stateless classless moneyless” society is only possible if the whole world is under one state socialist government first. However, what anarchists want is to go directly from capitalism to stateless socialism, which is impossible.
I think if Anarchism was feasible we would have seen a few examples of successful anarchist societies or nation but alas.