I was taking my morning constitutional one day, when I came upon a gang of toughs beating up some poor slob.  A second gang had taken an interest and were gradually edging toward the scene of the action.  A large crowd of by-standers had gathered to watch.
    "Goodness!" I cried. "What's going on here?"
    The head thug barely looked up from his labors, grunted, and aimed another kick at the unfortunate victim's groin.  The victim was thrashing about, trying to protect himself.
    "Those nice young men said they had to beat that guy up because he was armed and dangerous," said the by-stander nearest me.
    "Dangerous," muttered the head thug without looking up.
    "He doesn't look very dangerous to me," I observed.
    "Then it turned out that he wasn't armed, after all," said a second by-stander.
    "So why didn't they stop beating him up?" I asked.
    "Fer his own good," barked the head thug.
    "Now, hold on a minute there!"  It was the leader of the other gang. "Stop that!"
    Ah, I thought.  A good citizen to the rescue.
    "You're doing it all wrong!" continued the second gang leader.  "You've gotta aim for the kidneys!  And the head!  Here, let me do that!"
    "Whatta you know?" snapped the first gang leader. "I'm beatin' this guy up!  You stay out of it!"
    "But you're not doing a good job of it, are you?" replied the second gang leader.
    "Well, he keeps fightin' back," groused the first gang leader. "It's hard to get a good kick in.  You'd think he'd show a little gratitude, seein' as this is for his own good."
    "I can bring in more gang members," said the second gang leader. "That's what it takes to make 'im stop twitching!"
    "This is barbaric!" I shouted to my fellow by-standers. "We've got to stop this!  There are a lot of us.  If we tell them to stop, they'll have to stop!"
    "Oh, but we can't do that," said the first by-stander.
    "Wh-why not?" I gaped.
    "It's because the guy's in such bad shape," said the second by-stander.  Others were nodding in agreement.
    "That's right," said the first by-stander. "Maybe they shouldn't have attacked that man without provocation, but now that they're right in the middle of stomping the crap out of him, they have to see it through."
    "But someone has to help that poor man!" I insisted.
    "I agree," said the first by-stander. "It would be heartless just to walk away and leave him all beaten up like that."
    "And that's why they have to finish pounding the snot out of him," said the second by-stander. "The only valid questions for debate are which gang gets to pound him into little pieces and what techniques they use to accomplish that."
    "But the humane and sensible thing to do is to stop the senseless violence immediately!" I objected.
    "Stop beating him?  Entirely?" said the first by-stander incredulously. "Man, that's radical talk!  You're so far out of the mainstream, you're on dry land."
    "And don't forget," said the second by-stander, "that the guy keeps trying to fight back!  Do you want those poor thugs to look like wimps?"