Oh, to be sure, they are both dirty. Which is why a deep cleaning has been scheduled. The question is whether they are the dirt or simply have dirt on them.
The context of the cleaning is very different depending on whether a person is dirty or dirt. Therefor, the dirt could have appointed the dirty with the expectation of it being a fellow. Or the dirty could have appointed the dirt to expose it to the wash.
Ultimately, Mueller's and Rosenstein's actions are both going to be used by the administration to clean/drain the swamp. Whether or not Mueller and Rosenstein will come away, having defecated their past and being freed from the swamp… That is probably almost impossible to know without very intimate knowledge of what is on the heart (or lack thereof) of these men.