It turns out that Congressmen often spoke to an empty chamber. Knowing that, and not wanting to be embarrassed about that, both sides agreed that the C-SPAN cameras would never be zoomed out to show the chamber...the cameras (again, by mutual agreement) would be kept in close-up on whomever was the speaker at the moment.
And yet, Tip O'Neill decided one day to pull the cameras out to embarrass a Republican who was speaking as if to a full House. O'Neill had the cameras expose the fact that he was speaking to an empty chamber.
It occurred to me that if we fast forward to the Clinton years, and if Gingrich did the same thing to a Democrat, and if you cried foul about the evil GOP violation of the mutual agreement, and I said, "Hey...Tip O'Neill did it." You would then say, "Whataboutism. You are just like the Soviets."
The Dem strategy is to always be the first to violate a rule of law or ethics, and then when the GOP does it, you pursue their violation, and not allow "whataboutism" as a defense. It is a brilliant political strategy, but it is also cynical and unethical to the utmost. And, you make your unethical behavior worse when you act like you are being noble. You are taking the lowest road with this "no whataboutism" strategy, because you know that you are being two-faced about pursuing non-Democrats, and you don't want people to talk about that fact, so you are now trying to demonize "whataboutism" to avoid discussing the substance of your hypocrisy.