It's naive to suggest that the public has accepted climate change and even more so that it's anthropogenic. Once they do accept that, then the debate can move on to the difficult question of solutions, as you rightly point out; but for now, it's the deniers who make all the noise and stifle that much-needed debate.

Consensus is an important part of science, but it is not the only part. The scientific method is strong enough that the truth eventually prevails even if the current consensus is wrong (such as for your Einstein example). People who spread ignorance use the fact that consensus is not always correct to disregard it whenever it disagrees with their point of view. Hence "teach the controversy".