i think, i found the issue in your exchange:

it’s the way the two of you define “groups”.

the person you replied to defines a “group” as members of a social grouping; they were talking about rich people as a “group”.

you were talking about power being held by an unspecified, arbitrary “group” of no particular social membership; i.e.

to you, a democracy is a power structure that is “controlled” by a “group”.

to the person you replied to, the U.S. government is a power structure controlled by a specific “group”.

when they say “a minority group”, they are talking about rich people being a small percentage of the population, and thus a minority, which is making laws benefiting mostly themselves.

when you talk about “a group holding power over others” you are talking about an abstract, arbitrary, and undefined collection of people.

to you, a coalition of far-right fascists and far-left anarchists forming a joint government would be a single “group”.

to the person you replied to, that would be 2 distinct groups holding a portion of power.

you were talking past each other on different levels of abstraction.

which is why it’s no wonder you accuse each other of being disingenuous… because both of you didn’t engage in the same conversation…

at least that’s the impression i got, maybe i interpreted something wrong too… short text, like a forum comment, really isn’t well suited to philosophical discussions: way too much room for interpretation…