The recent brouhaha over Senator Larry Craig (allegedly) trolling for gay sex in a public bathroom highlights an interesting phenomenon: hypocrisy is bad, but why is hypocrisy the only evil the Left is willing to condemn?
The way the Left defines hypocrisy is: you claim X is wrong, but you do X anyway.
In the link above, Jesus defines hypocrisy differently: X is wrong, you claim to agree that X is wrong, but you really don't have any problem with X and are only posing.
(Here's the modern dictionary definition of "hypocrisy".)
You'll notice that Jesus and the Left differ in that to Jesus mere action doesn't prove hypocrisy, because to him hypocrisy is primarily a sin of belief: you don't really believe what you profess. Actions contrary to profession can certainly indicate that you may not believe what you claim to, but they're hardly definitive. How many of us never act against our deeply held beliefs? Acting contrary to belief should most properly be seen as a failure of self-control. "The spirit is willing, but the body is weak."
The Left doesn't see the world this way, because the Left generally doesn't give much credence to "beliefs". The Leftist philosophy is concerned with the moment -- what will give me the result I want now -- rather than with any overarching system of moral structure. The Left doesn't wonder if Senator Craig really does see homosexual acts as wrong, because the idea of self-condemnation is alien to them.
Which brings us to the big point: the Left's obsession with hypocrisy is due to their solipsism. The secular humanist sees no absolute right and wrong, so the only moral leverage he has is that someone, somewhere claims that something is wrong. That claim, however, can only be applied to the person who made it, because the secular humanist will admit to no morality other than what one makes for oneself.
This self-centered philosophy is a forge that can craft only a single weapon: accusations of hypocrisy. The Left can't say "you shouldn't do X because it's wrong", they can only say "you shouldn't do X because you claimed it was wrong".
Considering Senator Larry Craig, does the Left condemn him for seeking adulterous sex? For seeking homosexual sex? For trolling for sex in a public bathroom? For breaking the law? None of the above! Just try getting any Leftist to admit that any of those things are wrong in any absolute moral sense. They never will. If you ask, the only response will be:
"Well, Larry Craig opposed gay marriage, and now he's looking for gay sex in public bathrooms! What a hypocrite."