Creating a written record lodging a grievance against a specific faculty member is the definition of a complaint. That you personally would not perceive them to be a "complainer" and all of the stereotypes that may exist therein is a fair statement to make. It is less fair to imply that everyone across the admissions process will perceive it the same way—and the stakes for OP are much higher, and margin for error much smaller. Today's political climate doesn't help.
That you cannot claim what would happen with any degree of certainty is my point. For OP, sending this e-mail will not result in any kind of tangible benefit (though it may prove cathartic for a fraction of a second). They won't get a thorough investigation, or a report on findings. If the information is illegal to obtain, the adcom presumably should have ignored it as a matter of protocol. So, like you said, they may not even receive a response. It will not be longitudinally satisfying because even if internal cogs move, OP is left, again, totally helpless and in the dark.
If OP is rejected or on a perpetual WL from this particular school, they are left unsure if it is because their profile wasn't strong enough, because of their performance on the interview, because of their response to the particular question at hand, because they complained, or something else entirely. What they will know for sure is that they brought attention to themselves and ultimately did not matriculate. It will be difficult for them not to draw a straight line between action and outcome, whether it is right or wrong, simply due to the vacuum of information. Like I mentioned, the R e-mails don't come with elaborate rationales.
And, between us, if the interviewer is anyone of serious repute (a tenured faculty or someone with political capital), they aren't getting kicked off. You probably would already be aware of their colorful personality and the complaint would get filed away while the school circles the wagons to protect their ego.
I can appreciate the quality assurance argument, it just shouldn't come at the cost of OP's chances.