I'm not sure it's useful to blame any one single factor for an aircraft accident. Safety is all about having many layers of safety so if one is compromised somehow then other layers will correct it before it gets out of hand. Accident investigation isn't about attributing blame, but about finding all the weaknesses involved, and getting them resolved so that aviation is safer for everybody.
The pilots had minute to react to very complex situations, all while hurtling through the air and with inadequate knowledge. B engineers had years sat at comfy desks to build MCAS properly, with loads of peer review and years of experience, but still produced a lethal system that any engineer newbie could point out was lethal, relying on one sensor.
G