It's not acceptable, but it is rational.
Make no mistake, Mueller is fucking evil. For God's sake, read that Gohmert PDF about his history of fucking with investigations and giving passes to deep staters. He's a type of fixer for them… always has been, always will be. [RR] is all the same.
The Mueller investigation was always part of a plan to take down POTUS. When Sessions recused himself, they mocked POTUS and painted him as a fool because they thought the Mueller investigation was free to proceed without meddling from /ourguys. They were lulled into a false sense of comfort. As long as the Mueller investigation is allowed to proceed without involving /ourguys, the possibility of taking POTUS down lives on.
When Sessions resigned and [RR] was skipped over in lieu of Whitaker, that false sense of comfort was swiftly removed. This is why Schitt and the gang are going apeshit publicly about Whitaker.
Mueller is going to come up with nothing against POTUS as a result of this endless investigation, and probably has a (few) delightful sealed Huber indictment(s) waiting for him to reward his years of fuckery.