sure, politics is complicated and everyone bends the rules. but that would give a "background noise" that was the same for everyone. sometimes anyone can make a mistake. sometimes anyone can get away with it. there's no bias there.
if you catch someone who lies more than the others then the simple, obvious explanation is that they lie more than the others. if you want long words, then it's similar to the difference between systematic and stochastic errors.
in this context it's a little ironic to say this, but surely only a liberal who was so completely disconnected from reality that they have no idea of right and wrong would argue otherwise: some people lie more than others; you can tell who they are because they are caught lying more. to argue that there is no right and wrong in people's statements is "political correctness" taken to crazy extremes.
of course, there are exceptions: if you only check one person then it's unfair. but as far as i can tell (see my other comment) that is not happening here.