I agree that's often a normal problem, but in this case it may be that the author perceives the other side as mixing the two definitions, perhaps on purpose. B

I agree that's often a normal problem, but in this case it may be that the author perceives the other side as mixing the two definitions, perhaps on purpose. Because "public goods", in econ-speak, are things which basically have to be paid by taxes. To say that public transit is a "public good" in econ-speak is to say that it is in the same class of things as armies and police and law courts -- things which, by their nature, can never be supportable as a private enterprise. And, as I explain in another comment [1], I think that transit actually is a "public good" in econ-speak: Not the transit itself for the individual traveller, but the availability of good transit for businesses and communities. [1] https://news.ycombinator.com/item?id=35372130 https://news.ycombinator.com/item?id=35372130