The point of the rebuke of how badly she hurt him with this comment, was to turn it around and respond in the same way it would hurt in the opposite way.
The key statement in that phrase was "how would you feel".
She was affected and stated ...
She stated she didn't find him attractive enough via a toxic masculinity assumption.
As you felt charged about the response, it was exactly how he felt and many men would feel upon reading what she wrote in return.
If she desires sexual gratification through power role play, that should be done in the bedroom and should be worded so, and should not be tied to relationship and parenting and household activities.