He says They just kept posting more signs, because they were convinced that they were right. They believed that the right way to solve the problem was for peo

He says They just kept posting more signs, because they were convinced that they were right. They believed that the right way to solve the problem was for people to use the bin where it was located (that is, an empirical view as to what was the best solution, driven by a moralising attitude). His point is that their view was incorrect - false.