Cannabis induced psychosis is very much real and well-documented.
“Most people who use cannabis never develop psychosis. The clearest danger signals are high-THC products, daily or near-daily use starting in adolescence, and personal or family history of psychotic or bipolar disorders.”
What people fail to grasp is that the incidence rate of "Cannabis induced psychosis", while real, is NOT very well documented, because it's rare. The majority of incidents of "Cannabis induced psychosis" involve far more than just cannabis. They involve other substances, alcohol, and significant mental disorder.