It's easier to convince people who have no priors. The majority of people doesn't ever consider the temperature at the polar ice caps unless they are climate scientists, so they'll take accept it easily. But lots of people with a folkish understanding of local weather, specially after some huge snow storm, will mumble something like "so much for global warming".

Even if you put all methodological issues (and citations from Richard Feynman) aside or even whether corporate taxes work or not, lots of social science findings would seem dubious simply because they deal with human behavior, which is something which is almost impossible to not have an opinion on, specially because it attempts to describe our own behavior.

The problem is that, if I were to understand reality through my own behavior, it would be through an unwarranted generalization of my own conditions to the population as a whole. It's like that joke of "why don't they just buy themselves some money?".

That's one of the issues, at least.