The Soviet 3 year sentence was not "a show trial with a meaningless sentence". Nobody saw the trial :-) and the sentence was the worst in the Soviet system, and anyone receiving it would hardly call it meaningless.
I see all your points of view and understand them. It's human nature to want vengeance. The death penalty is a moral issue for me, and I'm against it. Tying someone down in a chair and murdering them when they're no longer a threat to society makes you no better than the murderer. I think that being imprisoned for life without hope is worse than being dead, although I know some will disagree. As far as financial reasons, if we didn't have the death penalty, we wouldn't have to bear the expense of appeal after appeal for years. I do see a difference in killing Bin Laden, as he was free and able to commit and instigate more murders, and killing him saved lives.
There were a few reservations in the U.S. However the few were drowned out by the multitudes cheering.