I don't know where you got the idea that libertarians oppose laws against pollution, but it's not the case. Libertarians do believe in certain valid roles for government; they are not anarchists.Simple example. A corporation dumps toxic waste. That restricts your freedom of movement and use of lands, and if it makes you sick, it further restricts your mobility and choices. Yet if the government tells the corporation that they can't dump the toxic waste or will be subject to fines and penalties, the libertarians screams that the corporation's liberty is being taken away. That is because libertarian ideology is premised on the false assumption that only the state can impair liberty.