Think about it... theres always some blood left in a cut of meat, you can't wash it all out. What about stock? You boil up the bones for gravy... whats in the bones that gives it the favour? bone marrow!
If JW's really wanted to adhere to their beliefs they would be veggies, but of course this would mean the bethal big wigs having to go with out their steak... so thats not going to happen!