That isn’t a universally true observation, but I do know what you mean. I personally think it springs from two things. One, many liberal activists get so caught up in being tolerant that they lose track of the fact that its OK to recognize that some things are just wrong. There are times when there is nothing wrong with just calling it like you see it.
Second, I think that some have become so preoccupied with the problems and wrongs in the West, that they end up becoming anti-Western. So everything that non-Westerners do seems OK, while that everything that emerges from the West is corrupt.
Now that I think about it though, I guess the problem all boils down to myopia. Whenever anyone conservative or liberal becomes so obsessed with their philosophy that they become blind to everything else around them, those people will inevitably begin to take on contradictory, and hypocritical views.