The argument you'd heard basically boils down to turning all power dynamics into moral categories: those who have power reinforce their own power by building systems that make sure there's no repercussions for their own actions if they harm someone under their power. The extension comes when people make it universal instead of specific: defining all human relationships in terms of power and its abuse. Those in power are inherently immoral, and thus under power are inherently moral.

There is certainly truth to this: normally, we would call such a relationship 'corruption of power', and as the adage goes, power and corruption tend to go hand-in-hand. The argument then goes that if you are not in power, the only way to return the relationship to a morally right state is to break the rules the corrupt powerful have put in place to purportedly retain their own power. If you grant the premise of the powerful making /all laws/ and /all institutions/ solely to preserve themselves and oppress others, the conclusion must follow.

The issue in my opinion is one of 'divined intent' - there is an implicit premise, that there is either direct intent built-in to those oppressive structures, or that there is indirect intent that carries the same amount of guilt for the powerful group. But that paints with far too broad a brush, and is really unfalsifiable, since we cannot fully know the mind of those creating and participating in those structures. Yet all too often, the argument boils down to an assignment of malign intent that vindicates any and all action in response. This is usually done with a motte-and-bailey: make the sweeping case that all powerful people think something, then tip-toe around individual examples when confronted, unless it's a cherry-picked target.

There is also the issue of the universal: this holds true of many systems, but not all systems, and not all people within those systems. The argument works by making the claim apply to /any/ relationship involving power.

Lastly, there is the issue of vocabulary. It's a cute trick to redefine words to apply only to a subset of what the words originally refer to, but the goal is confusion of language. You create new words to describe subsets of phenomena, but that's not what's been done in that argument: it hijacks the original meaning to generate confusion, often with the goal of saying, for example, 'if you are against racism [original definition], you will overturn all existing systems [modified definition].' There's equivocation going on in there.