That would have been a good argument when the political differences between liberals and conservatives were mostly on moral or social issues like civil rights and abortion and on economic issues like the correct balance between markets and government.

Those are things where there is no objectively correct position.

Now there are differences on things there this are objectively correct positions.

For example consider climate change. There used to be agreement on the underlying scientific reality, with differences in how to approach it. There was a group of top economic and science advisors from the Reagan and Bush administrations that were arguing for a revenue neutral carbon tax to address climate change and then let the market deal with it. The liberal approach favored more direct limits on emissions and the government more actively promoting replacements for fossil fuels.

Even as late as 2008 Republicans were still in agreement with reality on this. The Republican platform called for reducing fossil fuel use, establishing a Climate Prize for scientists who solve the challenges of climate change, a long term tax credit for renewable energy, more recycling, and making consumer products more energy efficient. They wanted to aggressively support technological advances to reduce the dependence of transportation on petroleum, given examples of making cars more efficient (they mention doubling gas mileage) and more flex-fuel and electric vehicles. They talked about honoraria of many millions of dollars for technological developments that could eliminate the need for gas powered cars. They also mentioned promoting wireless communication to increase telecommuting options and reduce business travel.

Compare to now. Now their position ranges from climate change being a hoax from people trying to destroy America to it may be happening but if it is Mankind had nothing to do with it and it isn't bad enough to be something to worry about.

So now any unbiased journalists writing on climate change or adjacent topics, or any unbiased academic working in these areas, is going to automatically be way more aligned with the left than the right.