> This is worse because the market not only has no way to price these cost but it is _blind_ to them. That you don't realize this means you think 'free markets' are 'magical'

Not the guy you're replying to, but you're wrong. This isn't a debate about effectiveness, it's about whether the tax is a free market solution or not. No one is arguing that the market isn't blind to it; this very well could be a case of a market failure and a tax may very well be the correct solution, it is not however a free market solution. A tax is government interference in the market and is by definition not a free market solution.