I know something else that came to mind...
I think that why passover is celebrated is because some things in the old testament were "cancelled out" (obviously my wording isn't correct) by the new testament & other things were not.

I *think* that might be why the pork thing is okay for JW's - because maybe it was cancelled out by the new testament. I do know that taking "the life blood" of another isn't okay & this has been interpreted by this faith from the new testament but I can't quite remember what the particular area in the new testament that this is from..

HTH