So what, that's not something under the patients control. You (as a society) can't (morally) go "oh, well some hospitals are malicious, so we're just going bank

So what, that's not something under the patients control. You (as a society) can't (morally) go "oh, well some hospitals are malicious, so we're just going bankrupt random people who get unlucky". The insurance companies should lobby to make that illegal, if it's already illegal lobby to have that law enforced (if criminal) or take them to court (if civil) or both (if both). In the meantime they shouldn't be shifting the liability to the patients.