Religious channels? Not all "public interest" channels must be of a religious nature. IMO, that would violate the separation between church and state. Furthermore, Echostar (Dish Network) is not allowed to add any more religious channels due to their agreement with Sky Angel.
Dish recently did add an interesting "public interest" channel, however, called The Documentary Channel.
http://www.documentarychannel.com/docchannel/
Beyond that one (which seems to have gotten some good reviews) DirecTV could consider adding Free Speech TV.
http://www.freespeech.org/
I suppose it's possible DirecTV is adding religious channels due to customer demand. I would be interested to know which other networks have applied and were turned down, and what reasons they were given.