Setting aside the issue of cults, recruiting from church networks is fairly common. It's not surprising and often not nefarious. After all, a church is just another social setting. People also recruit from other non-professional networks -- adult sports leagues, hobbies, alumni networks, family friends, and so on. Churches are just another social group.

I am, however, surprised more companies don't have explicit HR conflict of interest clauses regarding religious entities. Not whole religions, but specific congregations/parishes/etc. Allowing these social networks as unchecked recruiting channels without some sort of control seems like asking for discrimination suits, even when the subject is a traditional religious organization rather than a cult.

I think about religion the same way I think about family. There's nothing wrong with referring your cousin or fellow congregant for a position, but a judicious company should probably flag the conflict of interest in the actual hiring process and perhaps also in management relationships. Otherwise you can end up with centers of influence in the company revolving around an external religious social network, which is a huge risk for the company.

(Alumni networks have the same issue in terms of institutional political dysfunction, but with the important difference that a company cannot be sued for preferring Stanford grads in promotions.)