I believe right-wing conservatives have manufactured this notion of a 'liberal media". If I say this to someone else, they might laugh agree or disagree, but it's clear that it's only an opinion, and that it's not being offered with authority. If instead I claim to know this, it implies I've got objective evidence that it's true, and that this evidence is compelling enough that others can/should/do accept it as well.
What if I claim to know this about conservatives but fail to provide any objective evidence?
A short apology is in order: for the moment, the only examples I have of this kind of dishonesty are religious in nature. I don't want this blog to simply point to religion as the primary source of intellectual dishonesty, but I find myself struggling to find suitable examples elsewhere. If this blog ends up focusing too much on religion, I apologize. I'll try to not let that happen...
Theists often elevate their faith (aka. belief) to the level of knowledge in order to give it authority, and they do this being unable to provide the objective evidence that is required for it to be knowledge. If you're a Calvinist, you believe that sinners are saved only by the will of God - not works or repentance or faith. If a Christian asks how you can know that Calvinism is correct, you will point to the Bible.
In essence, faith is offered as evidence for the veracity of faith.
That's not knowledge. It's fundamentally dishonest to pretend otherwise.
Intellectual honesty demands that you accept the difference between knowledge and belief (though you don't necessarily have to admit it to other people). You shouldn't try to give more authority to the things you're unwilling to provide objective evidence for. Belief can be knowledge if you show evidence for it to a non-believer, and based only on that evidence, he/she concludes "hey, you might be right about that".