To a leftist there is no such thing as a "fact" meaning something that has objective truth/ Reality is a mental construct and is different for different people. I have argued against this very argument to no avail. I end with asking them why they feel they must fight to impose their system on others when they need only think it and it is real. The answer was, once anyway, well that's how my mind works and you are part of the trash that my mind throws up and I must overcome.
Is this insanity? Is it insanity when large numbers of educated people subscribe to it?