Hmmm.
I’m a fan of the old quote “If one side tells you it’s raining and one says it’s dry, your job is to look out the window”. It’s not about left and right. Sensible people on each side tackle the how not the whether. There are right and left wing solutions to the fact of climate change for example, the same with wages, immigration, culture, etc. But that debate can only happen if both sides have a shared reality.
Once you’ve got people believing their opponents are Nazis or baby eating Satanists, you get a lot of angry people who don’t think the others are fully human, and historically that’s .... suboptimal.