So let's ask the question the left never asks: how is it possible for an insurance company to pay for these giant medical bills? What makes it possible is a whole set of statistical calculations. For every person who needs open-heart surgery or chemotherapy, there have to be a certain number of other people who are paying their premiums but haven't gotten seriously ill. If the insurance company has gotten its calculations right, the expenses for any one person's catastrophic care are balanced out by the premiums other people pay "just in case."
You can see how Obama's demands undermine this whole system. To ask insurance companies to cover a patient after the tumor is diagnosed is to ask them to take on a known expense. Combine that with another Obama demand: that insurance companies can't charge higher rates for those who are at higher risk of getting sick. So if insurance companies have to take on a known expense and can't charge a higher rate for it, how are they going to pay for it? By raising everyone else's rates, redistributing their wealth to the new freeloaders.
This isn't insurance, it's welfare. And that's the whole point.