Anyone who thinks taking civilian lives to further your cause isn't cowardly is only fooling themselves. The cowardly act ISN'T the suicide itself. IT's hiding being your own death that is cowardly. It's the fear of retribution that's cowardly. It's not giving the innocent people a chance to clear the area that is cowardly. It's hiding behind your OWN CITIZENS that is cowardly.
You cannot turn an act this haenous into some kind of "spiritual warrior" bravery. That may be the motivator, but that certainly does NOT make it true, nor acceptable.
I hope the people that did this find that behind that death is their own eternity of hell.