How are military chaplains constitutionally justified?

Chaplains are schooled in the various religions that are practiced, not just what their religion is. I've met buddhist, christian, and jewish chaplains. They're mainly used as a conduit for counseling, scheduling family trips, or just the unit go-to-guy when you're having a problem and you need somebody to talk to. Stop complaining about "constitutional" and join the f*cking military.