“X depends on or is built up on Y” does not imply “X is Y”. Concepts, laws, techniques, etc. can depend or be higher-order expressions of QM without being QM. If you started asking a QM scientist about tensile strength or the Mohs scale they would (rightly) be confused.
I feel like you’re using “supercede” differently to the rest of us. You’re getting a hostile reaction because it sounded like you’re saying that EM is no longer at all useful because it has been obsoleted (superceded) by QM. Now you’re (correctly) saying that EM is still useful within its domain, but continuing to say that QM supercedes it. To me, at least, that’s a contradiction. QM extends EM, but does not supercede it. If EM were supercedes, there would be no situation in which it was useful.