For most people actual deaths are more immediately apparent than estimated deaths. By driving a car, riding a bus, or taking a plane any regular person also contributes to some of those estimated deaths. But this is very different from causing direct deaths by knowingly disabling a safety feature on a car, plane, or bus for example.
Company values. On one end of the spectrum you have a relatively small group of people cheating and no idea where the bucket stopped.
For Boeing you have multiple lines (not only the 737 MAX but the 777 too) going as far as handing over bribes to the FAA, with upper management investing the budget savings on some yacht time.