[Francis] Bacon thought of his inductive method as having two components, which he called the pars destruens (the negative part) and the pars construens (the positive one). The first was concerned with eliminating — as far as possible — error, the second with the business of actually acquiring new knowledge.People often expect both parts to come together. They want constructive criticism rather than just criticism. But Massimo goes on to argue that this is a mistake. Each part is valuable on its own, and if some people are more skilled at one part vs the other, it's useful to divide the labor. Massimo draws comparisons to the division of labor between theoretical and experimental physicists (an analogy that I approve of as a physicist).
I think people also believe that eliminating errors is somehow easier than creating new ideas. So if you're offering new solutions, that's a valuable service, but if you're revealing problems, anyone else could do it just as well. I think there is some truth to this belief. I criticize as a hobby, but the generation of new ideas and knowledge is more of a profession to me (ie scientific research). But most of the time, people just say criticism is too easy as a way of flattering themselves for having come up with an idea, and dismissing anything that could be wrong with their idea.