Chukas

In Bamidbar 20,12-Rashi Hashem gets upset at Moshe for hitting the rock instead of talking to the rock because had Moshe spoken to the Rock instead of hitting it, the Jews would have reasoned "if the rock which doesn't speak, doesn't hear, and doesn't need sustenance, still listens to Hashem, all the more so we should." Why on Earth would the Jews have made such a retarded Kal Vechomer? The rock doesn't have the choice whether to listen to Hashem or not, of course it listens to Hashem! In addition, the rock's not listening is not relevant! If anything it only shows that the rock wasn't listening to Hashem!