Well, there are mobs there, but the average level of the alliance RP community (that I have seen, bear in mind) is around level 80-85. So, the mobs wouldn't actually aggro, unless lower level characters came along, or the pilgrims walked right through each and every single mob before roflstomping it.
And Outland is a big place...the Alliance AND the Horde all thought that the orcs were all dead when Draenor became Outland. So, for all we know, there are still a good number of Fel Orcs out there. Besides, who here doesn't want to go smack in some alliance pilgrims even?
It may not be needed to be Fel Orcs though...we could just be normal orcs who worship the demons and have broken off from the Horde. Just trying to get an idea for anyone who would actually be interested.