I think there is partial truth here. Part of the legislation does revolve around deciding which procedures will and will not be covered. This is intended to control costs. As it is, insurance companies are doing the same things and have been for years. They don't cover everything, some things require more out of pocket cost than others, and some things are just not covered at all. Mental health for example is not covered by many insurers. "non essential surgeries" and preventative care measures are other good examples. Many alternative treatments like acupuncture, massage, etc are also usually not covered. Someone has to decide what is essential and what is not. It is not reasonable for a healthy person to get extensive health screenings once a week for no specific reason for example. They can't cover everything for everyone.
Unfortunately, someone or some group has to draw these lines. What is reasonable and appropriate and what is not? What should be paid for and what should not? Some might say, for example that a hip or knee replacement for an elderly person confined to a wheelchair should not be covered. Others may think that mental health is not an important thing to cover.
Difficult decisions have to be made. There must be people on panels who make these decisions. There are so many potential circumstances that no matter what those decisions are, it will inevitably not apply perfectly to everyone. That does not mean these are "death panels." just normal people charged with making difficult and sometimes unpopular decisions.