I couldn't care less what the actual ideas are, or whether it's biased or not. A lot of the time they take the ideas and word them extremely cleverly.
It's not the fact that they are political, it's the fact that when a lyricist sits down to write a political song he wants to sound as clever and educated and intelligent as possible, so as to make it better than just "fuck Bush" or what have you. Political lyrics force the lyricist to push the limit of his abilities so that he can get his point across effectively, and that results in very clever and good lyrics. I could give a fuck less what the idea is most of the time in songs unless the idea or story or whatever resonates with me in some way, so when I listen to lyrics I'm looking for clever and new ways of putting the ideas down. Another excellent example is Islamic calls to prayer. I'm not a Muslim, so I don't care that they are calls to prayer, but they are still beautiful to me. I'm looking more at the form and less at the ideology.