Does the Affordable Care Act "soak the young"?

Avik Roy revives the complaint that formed the emotional core of the legal case against the Affordable Care Act: that the act shafts young adults by forcing them to buy coverage that effectively subsidizes insurance for older adults. Here's the basis of his complaint:

Under free-market conditions—what insurance pros call experience rating—the typical 18-year-old costs one-sixth what it costs to insure the typical 64-year-old.

But Obamacare, in a sop to the AARP, requires that insurers only charge three times as much to their costliest beneficiaries what they charge to their least-costly ones. As the illustration below shows, this increases the cost of insurance for the young by 75 percent, while offering only a modest 13 percent subsidy to older Americans.

Before moving on to the core alleged problem, let's note a couple of sleights of hand at the outset: