If you accept this, then the question might turn to how it was possible for the FAA to be weakened to such a degree that this corporate influence was possible. FAA are the regulator - at the end of the day, safety lies with them. Perhaps it's the responsibility of committee and congressional oversight to the aviation regulator? Perhaps the buck stops with the government representatives who have allowed this mess to be possible in the first place?
Ironically, however, Europe has called the FAA to task before on several models of Boeing aircraft that weren't implicitly design safe. See the D.P. Davies Interview w.r.t the Boeing 727 certification process.
They cut corners, and did not inform pilots of the inherent risk that existed in a manner concomitant with the severity of the result. This originated in a desire to submit an aerodynamically deviant aircraft, yet attain type airworthyness certification with minimal friction.
Lion Air may be last in safely operating aircraft, but the design standards were generally written in such a way where even the worst operators stood a good chance of going up, and getting back down free of harm.
Obviously, that is no longer the case.
The FAA confirmed the discussion and that it deemed the issue "low risk" at the time.>
So the FAA is culpable as well as Boeing