Good point, Dicho. The Digital Tradition category for spirituals is @spiritual. If I put @spiritual in the blue search box, I come up with just this (click) a list of songs that have that @spiritual designation. If I put @spiritual into the Digitrad and Forum Search (SuperSearch), I come up with a list of every song and message that has the word "spiritual" in it. I'll pass the information on to Max and Pene and see if they can come up with a solution when the next edition of Mudcat comes out.
Note: the @spiritual category designation isn't perfect. You may also want to try @gospel, @religion, and @religious. Even that won't bring up 100 percent of our spirituals - we're human, and somethimes we miss a few.