I didn't suggest that you thought people should not be punished for failed attempts at mass murder, just that you seem to rank them lower on your list than the ones who succeed.
The law infers intent when an act is sufficiently wanton and malicious. I would say setting off a bomb in a public place constitutes a sufficiently wanton and malicious act.
I'm not persuaded of their good graces by the fact that they provided advanced warnings of their bombing. If you set off a bomb in a public place, you don't get to say "Geez, I didn't mean to kill anyone," or "Hey, we warned everyone" if someone dies.
Setanta is correct in pointing out that the Greenwich Village explosion (that thankfully killed Weathermen and not innocents) involved a mishap with a nail bomb
they were constructing. Nail bombs are intended to kill and maim, not to simply destroy property.
That the Weatherman have said they never intended to hurt anyone doesn't hold much water with me. As the Greenwich Village incident indicates their strategy was apparently changing, and even if it had not, repeated bombings of public places was eventually going to result in casualties.
There is a point beyond which there doesn't seem to be any rational reason to assign relative "badness," unless it attempting to somehow excuse or rationalize the evil someone or some group has perpetrated.