Are there any secular country music groups?
For that, you’ll have to look in to the non-mainstream. I think Ryan Adams may be secular, although I don’t know if he’s ever declared what he believes regarding religion. Steve Earle’s lyrics are pretty secular as well, although I believe he may have declared himself a “born again” when he jettisoned the drugs and alcohol.
Many of the performers start out in Church bands, or choirs. But with a pentient for partying, that would rival most rock bands, you could say they are "Christian" on the outside, but completely secular on the tour bus.
They’re really no more hypocritical than most so called Christians. They’re just like that idiot in Kentucky who refused to sign marriage certificates for gay couples but is on her 50th divorce... whatsername? The only difference is, they happen to be famous.