About half the population of Louisville is (self-identified) Catholic. About a third is Southern Baptist. The rest are everything else.
So, assuming he has a large number of co-workers, and assuming they're representative of the population of Louisville, you ought to expect about half of them not to be Catholic, and about 30% to be professing "born-again" Christian of an evangelical Protestant sort.
Perhaps his co-workers are in fact not very representative of the population of Louisville, perhaps because they're more representative of the population of, say, Guadalajara. But that's speculation. (Just sorting the packages that Americans won't sort, and all of that.)
The article implies pretty clearly that persons who have only been in a Catholic church have not gotten any sort of Christian witness. I seem to receive a pretty strong "Christian witness" everytime I enter mine and look up to see the crucifix, with its harshly realistic depiction of the price Christ paid to free me from my sins, but c'est la guerre.
But still, leaving aside the strictly religious side of this, snaps to the guy for standing up for witness FOR Christ having as much right to be made as witness against Him, and snaps again for his saying it to his boss like that.
And general horror at the "cross as bling" fashion.