About the transaction costs issue... how do class action lawsuits rate in terms of transaction costs?
I'm with you that the libertarian approach is somewhat worse on the effectiveness scale than what we're capable of doing in our current system. But I'm not going to go so far as you and say it's nonsense.
A current issue in my area (Minneapolis metro area) is 3M's PFCs contaminating ground water in Lake Elmo, Oakdale and Woodbury. 3M released these chemicals into the area starting in the 1940s, when their health and environmental effects were not known. Regulation would therefore not have helped in this particular case.
The court system is working, though: the State of Minnesota is suing 3M for damages, and 3M is engaged in clean up. Note that this lawsuit is not alleging an infringement of regulations (at least, not to my knowledge), but instead is focused on 3M having negatively affected property regardless of intent.
This is one example of the court approach working (I've got my fingers crossed that 3M's gonna lose).
My point is, framing it as a property rights issue and handling it in the courts is a helpful thing and not nonsense.