On authority is used to justify the fact that many communist movements of the past turned into brutal dictatorships and that “it’s fine actually that mao starved half of China because you can’t have a revolution without being authoritarian”.

The actual paper is short and kind of stupid. What Engels was arguing in that short essay with a ridiculously outsized influence was that he was technically correct (the best kind) that anarchists are silly because any type of government someone could propose inevitably involves one person imposing their will on another like your quote says.

Really what Engels (who was a prominent communist thinker) was doing was fucking up any attempts at communist organization because now 1/3 of communists think that brutal authoritarianism is based and necessary for a revolution.