The simplest action is nuclear, why do no prominent climate activist groups support this? Why is the solution always something stupid like giving toxic chemicals to cows or to switching to paper straws when drinking out of plastic lined cups?
The answer is simple: They want societal collapse, and the reason why they are getting more and more violent and switching to other causes is because the societal collapse promised to them by climate change is not coming, and it looks like it will never come.
People are proposing comparatively minor fixes to avoid unmitigated disaster.