I have much more sympathy for Pearl. He's constructed "toy" problems that yield different answers depending on the hidden causal structure chosen. He then shows that unless one takes account of the causal structure, it's impossible to correctly answer the problem. The logical conclusion of this is that any technique that doesn't use the causal structure as an explicit assumption is instead using it as an hidden implicit assumption. His hope is that anyone who goes through his exercise will come to the same conclusion. Starting with real-world problems is tricky, because one doesn't know the correct answer in advance, thus it's much harder show the reliance on the assumptions.

Consider a parallel with computer programming. A user complains that they fear a program is giving them the wrong answer on a complex real world problem. They report this, and get back the unhelpful answer "Works for me, will not fix". Unable to shake the feeling that the answer is unreliable, they reduce the problem down to a proof of concept that serves as a simple self-contained test case. Two different inputs produce the same answer, but only one of them can be right! But now they are unable to convince the maintainer to even look at the test case, because now the maintainer says "I need to focus on the real world, and don't want to waste my time on toy examples".

It's a discouraging position to find oneself in.