LOL.. w/e Dave. There's always going to be bad apples. I guess you don't believe in Heaven either.
It's not meant to be an actual place, what Lennon said, but more of an ideal. A goal.
You could make the same argument for the Bible... and say...why bother with not killing your brother of neighbor...someone's going to do it eventually.

LOL.. I see where you are headed with this...
"He would gather a group of like minded individuals to help him. Soon they would control all the bread and water"
The only thing stoping a bad guy from trying to take all of my bread and water is a good guy with a gun.

I think I'll stick with Lennon...tyvm.