We too easily forget (as do many of the academics working in public administration) just how many public sector positions would provide absolutely NO use to any partisan cause by being selected for on a political basis. That is not to say that partisan hiring (or in this case, NON-hiring) for certain positions close to, or at, the policy table, would have no consequence. But the person who delivers the mail, or even a guy like me, does what they do, the same way, regardless of who is in office.
There probably IS a gray zone where the tendency of managers to hire those they feel sympatico with, or folks they think will not confront them, overlaps with politicization of the hiring process. In those instances, it is more like classic favoritism, flavored with politics.
And, in some respects, particularly if the hiring manager is, themselves, in the sort of position/function that is very close to the policy table, politicized hiring is, in their minds, somewhat akin to hiring people with enough expertise that you don’t have to train them. They’re ready to go, Monday morning, and no explaining is required about why you want to do/approach something a particular way.
As someone working in a federal agency tasked with (among other things) assuring the political impartiality of the public service, you can imagine I am a little uncomfortable with that sort of hiring, given that it poses risk to merit, and sidesteps the “fearless advice” that public servants are supposed to provide to their political masters. But at the same time, I can understand the manager’s perspective, and how easily they can slip into it.