This article in Politico strikes me as an example of shoehorning the facts to fit a narrative that the writer has decided to tell.
Michael Calderone makes it sound as though no journalist ever took a job in a Republican administration.
The highest profile such case in the George W. Bush administration was the late Tony Snow, who left FOX News to become White House press secretary. I wouldn't be surprised to find out that, historically, that revolving door has more often led into Democratic administrations than Republican ones, but I don't think the picture is as black-and-white as Calderone paints it.
And given the current economic realities in journalism, that Calderone describes, my guess is that at least some of the journalists in question would have viewed jobs in a McCain administration as a welcome alternative to unemployment.
I've previously mentioned how many senators President Obama has appointed to high office, in contrast to the governors that Bush appointed. In any sort of hiring situation, whether in the public or private sector, one gravitates toward candidates with whom one is familiar. Obama's Washington experience was in the Senate, so he has often looked there for job candidates. Bush, by contrast, had experience as a governor, so he appointed some colleagues from that group.
Everyone in government becomes familiar with journalists, whether they want to or not. So it's natural for those in government to consider journalists when hiring.