The ACA didn't outlaw PPO plans. A better analogy in this case would be if government offered subsidies to chicken farmers because chicken is healthier for you than beef, and so consumers started choosing the cheaper and healthier chicken patties, and then McDonalds stopped carrying cheeseburgers because not enough people were buying them.
I disagree with this analogy. The issue the original poster was talking about isn't subsidies. (As far as I know you can get ACA subsidies for plans offered through the exchange regardless of whether they are PPOs or HMOs, correct?) Rather what has happened is that the ACA changed the services which have to be provided with every insurance plan, which increased the price of insurance.
Now I happen to think that it is a very good thing that the government mandated that, for example, your health insurance cannot come with a lifetime cap on benefits, and if you get sick your health insurance company cannot go looking back through your health records to find retroactive reasons to deny you coverage after you've been paying premiums for years. But both of those changes did increase the cost of providing health insurance significantly.
So the analogy would still be more accurate if it was: The government mandates that every meal sold by restaurants has to come with 16 oz of fresh broccoli. Because broccoli is expensive relative to what is normally in fast food and fast food consumers are price sensitive, McDonald's cannot raise the price of a big mac high enough to cover the per unit cost of the broccoli and still make a profit, so they stop offering that, and only offer chicken sandwiches.
McDonald's actions are motivated by trying to maximize profit/minimize loss, but the root cause isn't economics, it was a change in the regulatory environment.
No one's rights have been infringed in this hypothetical sandwich situation. The constitution has not been violated.
I agree with this statement, but that still doesn't make the change a purely business decision. It's a direct result of changes in the rules for what kind of insurance plans can and cannot be offered. (Which, again, doesn't mean I think those changes are bad, just that they are were regulatory decisions, not business decisions.)