Is Medicare "junk" coverage?

A commenter at Megan McArdle's place points out that, by White House standards, Medicare is junk coverage that should be outlawed like meat infested with e. coli.  Medicare is essentially catastrophic coverage strictly for expensive hospital stays.  Of course many seniors also want coverage for expensive, frequent office visits and prescriptions, and there is coverage for that.  Voluntary coverage.  Voluntary, private coverage for which they pay their own money to insurance carriers in the private market.

We can't just let people make up their own minds about whether to carry only catastrophic coverage, right?  That would be like letting them drive a Ford pinto.  And we can't expect them to pay for their own coverage beyond the catastrophic level, right?  And yet, as the commenter points out,  what Medicare makes optional for vulnerable seniors, Obamacare mandates for young invincibles.

In other news in bizarro-policy world, maternity care is now mandatory for the middle-aged but optional for women under 30 years of age, who are the only ones now legally permitted to buy bare-bones catastrophic coverage.