Folks, I think you're mixing different issues here.
The OP noted that news anchor Chase Gillmore is also a preacher on weekends. FilioScotia then opined that was a good thing, assuming that a preacher would at least be more knowledgeable about religion than the Houston TV reporter he brought up. Unfortunately, that doesn't necessarily follow. Becoming a preacher doesn't necessarily require someone to learn about religions other than his/her own.
The converse isn't true either. Many atheists are quite educated about all major religious traditions, if only to improve their debating skills.
I think we all expect reporters to be reasonably knowledgeable about the topics they report on, including religion. But we also want them not to have any hidden agendas. If they bring their own perspective to the news, the viewers should know what it is.
Those are two different things, and being a preacher doesn't guarantee either passing the first test or failing the second.
Whether Mr. Gillmore passes those tests is something for his viewers to decide. As for whether he's able to report stories involving Muslims without bias, well, there are already plenty of non-preaching reporters with problems in this area.
BTW, I'm quite skeptical that anywhere near 85 percent of reporters "profess to have no religious beliefs" in the US, where only about 15 percent of the overall population describe themselves as non-religious. This sounds like a misstatement of a 1982 (not "recent") survey by the libertarian-leaning Cato Institute (which, depending on your views, you may not find "credible") which concluded that 85 percent of
Columbia Graduate School of Journalism students (not journalists in general) identified themselves as
liberal (not irreligious).
Here's the link to Cato's study, if anyone cares:
http://www.cato.org/pubs/journal/cj20n3/cj20n3-7.pdf