I've actually argued a couple of things.
The first is that there are things that only government can do, like draft laws, enforce laws, etc. There are things that the government is currently doing that the private sector can do - like staffing ferries, filling potholes, or running a port facility. When the demands on tax revenues exceed the economy's capacity to finance them via tax revenues, and you can't fund everything that government currently does - it's best to focus government on things that only it can do.
The second is that even in those domains where government is the only entity in society that can provide a given function, the government has a responsibility to use public funds as efficiently as possible.
That's it.
Consequently - I think that, say, spending 70 million dollars subsidizing a port facility, instead of leasing it to whoever can operate it for a profit is a completely unjustifiable waste of public money.
Instead of generating money for the public via its operations, public money is funding it's operations to the tune of 70 million dollars a year.
"Port of Seattle reduces tax bite on property owners
It may be a first: the Port of Seattle commission voted on Monday to approve a 2010 operating budget that will reduce the amount of tax dollars the port collects from King County property owners over the next year.
The port, which has the authority to tax property owners without voter approval, decreased the amount they will collect this year by about $2.4 million - dropping the total amount they will receive down to about $73.5 million."
All things being equal, I can think of quite a few more legitimate and effective uses for public money. Evidently some can't. That's fine - but I find it endlessly amusing that as a consequence of that I'm the "regressive."
once need only look at Heathrow Airport to see how shitty private run ports can be.