Earlier quoted context omitted.
Because those in the middle and upper class have employer-paid health insurance which protects from the worst of bills. You only go bankrupt if you're uninsured and usually only those in the lower-middle or lower class are uninsured. And those in the lower echelon of society economically are those least able to have the time or money to march or lobby for change.
I went to ER a couple of months ago for a relatively minor issue and stayed for a few hours total. This was in-network hospital, doctors and so on. Purely by co-pays this ended up being a ~$800 bill after all the insurance kicked in. If I didn't have a comfy software engineer salary, and instead lived paycheck to paycheck, this would've been devastating, even with insurance.
Insurance was billed ~10k, with coinsurance I had to pay $1,400. This is after the hospital billing in multiple rounds and forgetting to bill insurance on one of them and also forgetting to send the bill to me (which if I hadn't been proactive about following up with would have led to it getting sent over to collections).
I'm assuming I have better health insurance than a decent percentage of the population and I can afford the bill but how the hell can most people? What a terrible, terrible choice for someone to have to make between getting care when they're at their most desperate and avoiding financial ruin