You know what's weird? A single-payer supporter suggesting that mandates are bad. Oddly, I've witnessed more than a few very progressive single-payer people inexplicably lashing out about the mandates in the House reform bill. One of whom is pushing for the entire reform effort to be abandoned in part due to the mandates.
Now, I hasten to reiterate that I ultimately support a single-payer system, but in the current political and economic climate a public insurance plan would be the best and most realistic path to achieving single-payer.
However, there's a misunderstanding floating around that single-payer would somehow be free or optional or completely divorced from profit-making. In reality, it's none of the above. Single-payer would be "mandatory" insofar as we'd all have to help to finance it in some way, via higher taxes or premiums. And as with most other single-payer systems, the "payer" -- in this case, the federal government -- would still be paying private for-profit companies. Hospitals, doctors, equipment suppliers, and, yes, evil drug companies.
Of course the government would be negotiating lower rates, but the government would still be paying/subsidizing for-profit industries in the healthcare sector. That's how it works. Unless we were to choose the British system and nationalize everything. But good luck getting that one through Congress.
By the way, without mandates, premiums will inflate regardless of whether we're dealing with a mixed public/private insurance system or a single-payer system. One of the reasons being that many people will game the system -- only enrolling when they're sick or injured and bailing when they've recuperated. The subsequent shortfall in the fund would have to be recovered somehow. And so, higher premiums.
Put another way, you can't ban discrimination based on pre-existing conditions and have lower/competitive rates without mandates. Medicare, for example, has to take everyone 65 or older. And you can't decline Medicare coverage, but then suddenly enroll after you become sick. So Medicare is, by in large, mandatory (you can opt out, but you lose your Social Security benefits as a penalty).
I know. On the surface, mandates still sound scary. But as it stands right now, there's a public option as an escape hatch to avoid the compulsory hand-out to the private cartel. If you're poor or struggling, there will be subsidies to help you. And if you're receiving insurance through your employer, the mandates are irrelevant.
Meanwhile, there are indeed problems with the House bill. Rates ought to be tied to Medicare, and there needs to be a way to prevent the private exchange plans from dumping sick people into the public option. But what we have right now is a solid base on which to build, and no matter how you slice the House bill, it's infinitely better than nothing.