Where Have all the Pally's Gone?

Last night we tried to finish up a Naxx-25 PuG from the night before. 20 raiders waiting to go...tanks, dps, raid heals.....no pally's =(

We had absolutely no tank heals. Guildies weren't on, friends were saved-- but really??!! No friggin tank heals? No priests, no pally's. /sigh

How does that happen?