There just seems to be a misunderstanding on the intention of a though experiment here. There is a subtle implication that because the thought experiment is "contrived" that its less valuable. When thinking about philosophy, a core part of philosophy is to reduce concepts, ideas, or beliefs into abstractions (or a "spirit" or "essence" of what their intention is), the thought experiment presents itself as a perfectly…
I don't think the author's objection is to thought experiments in principle but rather, to the way they are composed and used. After all, a thought experiment that only holds true given an impossible premise would have no rhetorical power if we weren't willing to extrapolate our conclusions beyond the premise, to the possible. Which we are - that's why the trolley problem is taught to people who aren't railway signal…
I view it like a black box where you can define inputs and observe the output and your goal is to understand what calculations are made inside. Thought experiments are essentially fuzzing it to understand what's happening. "What if it's a fat guy? What if it's a smoker? What if it's a politician? What if it's a homeless person? What if there are 10 people, what if there are a million?" and you're iterating over lots of options to get closer to understanding the formula.