One explanation for hospitals filling up is that there was a major fear campaign happening in the media, and many people use the ER as a doctors office. Many doctors office at the beginning of COVID were refusing to see patients that exhibiting any cold like symptoms, so people had no choice but to go to the ER, which undoubtedly would have increased the spread.

2nd, there is a mental component to sickness that is apparent when looking at placebo effects in studies. If a patient is deathly afraid of COVID and catches COVID, they can in fact worsen their symptoms and sickness based on that alone. If media is convincing people that COVID-19 is incredibly deadly, it can become deadlier than if you are not someone who worried a lot. This is nothing new as there has always been a component of care for cancer patients that involved mental health. Watch Patch Adams to see what I'm talking about.