Public transit also imposes a cost on everyone else -- most of it is subsidized by taxes and will never be profitable.

Public roads and public transit are both funded by taxes, so I don't see why it would be right to use one but wrong to use the other.

I think you could make an argument for the cost-effectiveness of transit and walkability compared to car culture. It lowers the base economic hurdle to be productive in society and is more environmentally friendly to boot.

I think it's fine to enjoy public roads and driving a car as a personal activity, but I think it gets too much public funding as "the default" in North America. I'd rather my tax dollars go to a train line than a highway lane.

Most public transportation is partially subsidized in the US. Car owners are paying taxes to support public transportation via income tax, sales tax and/or a gas tax.

Roads and highways are also subsidized. Fuel taxes and vehicle fees would have to be raised substantially for drivers to pay their own way.