Being a liberal (the philosophy) is equivalent to being neutral and objective according to all the mainstream media, which are all liberals.
As someone from the UK, a country that is pretty far to the right of most of Europe, and yet still far to the left of the US, the idea that these publications are biased to the left is, frankly, laughable.
https://www.vox.com/2016/4/21/11451378/smug-american-liberal...