Krugman has literally the worst record of any economist not only in recent memory, but of all time. I don't know how anyone takes this clown seriously. Don't forget, in the early 00s he predicted that the internet would be no more life changing than the fax machine, selling products on the internet via Amazon and eBay is a worthless fad that will pass in a year, and how there is no such thing as the housing bubble and to keep buying.
When I took macro econ course in college my text book was co-authored by Ben Bernanke, it was actually bretty gud Ben "Please take this the right way, but Hilter Had Good Economic Policies" Bernanke clearly understands the theory and limits of macroeconomics, even if he didn't accomplish anything as the Fed head. Any intro econ class that teaches the Communist Manifesto is clearly pushing propaganda by a teacher who does not know the basics. Later in life Marx made some mathematical models that are somewhat interesting, but that's more of something a graduate course would dig into and rip apart. In my experience, most econ professors are some form of lolbergs and dismiss the Communist Manifesto and socialism with a laugh.
Nash clearly does have mental issues, and probably has some form of schizophrenia. This is based on watching interviews with him and his son (another brilliant mathematician) who was also diagnosed with schizophrenia. There is not just one type or cause of schizophrenia, and they usually lump all the outward symptoms of “crazy” together. The modern DSM is for insurance billing purposes, not for illuminating the underlying causes of mental illness. Nash could have born with a genetic predisposition for schizo, got too close to something he wasn't supposed to, and the cabal stressed him until it was triggered. Also every time I learned about Nash in college, the professor would give a twenty minute aside on how he is an anti-semite, and a “really nasty guy in real life.” Nash was clearly on to a lot more than is publicly admitted. Nash's name cannot be brought up in a classroom without his name being slandered.