So I've made this sort of argument before in a somewhat more limited form. The analogy I like to give is that we don't spend multiple semesters in chemistry discussing the classical elements and phlogiston (even though phlogiston did actually give testable predictions(contrary to some commonly made claims on LW). We mention them for a few days and go on. But in this context, while I'd favor less emphasis on the old philosophers, they are still worth reading to a limited extent, because they did phrase many of the basic questions (even if imprecisely) that are still relevant, and are necessary to understand the verbiage of contemporary discourse. Some of them even fit in with ideas that are connected to things that people at LW care about. For example, Kant's categorical imperative is very close to a decision-theory or game theory approach if one thinks about it as asking "what would happen if everyone made the choice that I do?" Even Pearl is writing in a context that assumes a fair bit of knowlege about classical notions. What is therefore I think needed is not a complete rejection of older philosophers, but a reduction in emphasis.