"The practice of claiming to have moral standards or beliefs to which one's own behavior does not conform..." Several arguments. All of them fascinating. So let's start with Machiavelli. His point was that we people "..are often touched more nearly by appearances than by reality." In the 1980's in a study subtitled Social Expertise and the Evolution of Intellect of Monkeys, Apes and Humans, agreed when they titled their study Machiavellian Intelligence. It's easier to seem fair than to actually be fair, and because laziness is deeply ingrained in human nature, humans more often choose appearance over reality. Then if you think about this in terms of yourself, unless like me you're an unrecognized Saint, you can grasp the soundness of this position. And you got Benjamin Franklin who said something like "..a convenient thing to be a reasonable creature, it allows you to make a reason for anything you have a mind to." And here laziness gets in the way of the hard work of trying to find accurate evidence to support your position and easier still to pick and chose what evidence best suits your position. The truly challenged by reality of course just make stuff up, then allow the theoretical underpinnings to become increasingly divorced from reality rather than accept the possibility of being in error.
Philosophers have tried to work out whether or not Hypocrisy is good or bad. Philosophers worth their salt never have answers, but they love a good argument. Generally in moral terms Philosophers see it in terms of "pretending to be activated by a motive other than your own motive." This comes under deceit and lying which may or may not be a good thing. Philosophers also suggest that a "hypocritical lack of moral seriousness" can very much depend upon certain assumptions about the extent and make up of a moral framework within society, and so, they go on, best to think of the "No-Hypocrisy" position in terms of the right to blame and the value of blaming to the more constructive processes worth encouraging within a good society. There's also the idea that hypocrisy is a disposition in some to blame others and at the same time an unwillingness to accept blame from others or to blame ourselves. Realists more often just come out and say that being a moral person is a huge struggle in which most of us fail, so accept the flaws, we're all sinners, for god's sake everyone realize this, so get on with it and compromise. Karl Jung, who really did feel sorry for us people attempted to improve our lot by suggesting that under all circumstances lying to ourselves was very, very unhealthy, we had to know who and what we are and as we decided what we wanted to be, otherwise we all end up nutty. For Jung, I'd like to think, the west is enjoying yet another endless therapy session.