Yep, the issues started way earlier than the software. In fact the software is at the very end of the chain here, unless you also want to insert "no training". It all started when they wanted those big engines crammed into an airframe not designed to hold them, so as to try to quickly catch up to shifting market demands being met by Airbus.

I just sounds like nobody really thought about the consequences of MCAS triggering due to faulty AOA sensor input. There should be a dedicated switch to disable MCAS without completely disabling the electric trim motors.

This sort of buck passing is what kills people. The software may have performed according to its specification but it didn't do what it was supposed to, or it wouldn't have crashed the plane. Now sure, we could identify where things went awry in the chain of steps from "make the plane fly right" to a detailed functional spec, but when it comes down to it, the software was meant to "make the plane fly right" and it did not.