The problem ...
I don't think you should be able to throw your shoes at somebody and not have any punishment whatsoever. If he just went to jail for a few days I wouldn't have any problem with it, but they do seem to be taking it too far. In the overall scheme of things it wasn't that bad.
The problem is that it could have been an explosive, and killed more than W.
That's always the problem. Jokes are easy to get over. But the next time someone assumes it's just a publicity stunt, more than just the intended target or -- even more often -- not even the intended person gets killed. That's the very real and common problem.
In a nutshell, we
should all "laugh this one off." But also give the warning, "if you try to throw something, don't be surprised if you're shot before it leaves your hand." That's thhe simple security warning that needs to be made.
Every day unarmed people get shot for doing something stupid, and people cry about it. But the reality is that the person could have been lobbing something more than a political statement. In fact, someone might attempt that now because it's considered a political statement.
After all, what better way for an extreme rare, rogue person to further the cause of his beliefs than to sneak a bomb into a rally. Innocents die all-the-time because just one, rare, single person decided that "friendly fire" is a great way to change people's minds. It's worked throughout history.