Public Option and Competition

I'm a little bit confused by the opposition to a public option to the for-profit health-care choices that dominate our system.  On the one hand people are concerned that these programs will be a drain on public resources.  Then, without missing a beat, we are told that such a program ... even one without public subsidies, would present unfair competition to insurance companies. 

In general, most people leveling these criticisms believe them.   honestly intended, but inconsistent.  I mean, either the system is so inefficient that we can't afford to offer it, or it's so efficient that it is unfair competition to 'for-profit' competitors. 

The reality is that it is neither.