The simple reason why classical gravity can entangle

Ever since gravity-induced entanglement (GIE) experiments have been proposed as a witness of the quantum nature of gravity, more and more theories of classical gravity coupled to quantum matter have been shown to predict GIE, despite the existence of several theory-independent no-go theorems purportedly claiming that it should not be possible. This note explains why this is possible, and why this makes the study GIE experiments, and low-energy quantum gravity effects in general, an even more urgent matter in quantum gravity research.