I think it could be fun either way! Maybe droids DO have readable minds, but they're glitchy and weird—like the trippy fractal bizarreness of Deep Dream. Alternately there's just a void where Hux's thoughts should be, and that's how Ren starts to figure it out. His choices are suddenly: Hux is Force-sensitive enough to block Ren entirely OR Hux is a robot—and he immediately decides that sycophant's a ROBOT, because the idea of Hux being a Force user is just fucking upsetting.