Responsibility is a tricky thing in tragedies like this. In hindsight, yeah, Boeing undoubtedly should have made more noise about this possible failure condition, and/or tested the system better, and/or designed the stall-prevention system to deal with sensor failures more gracefully, and/or redesigned the wing, and/or spent more time on their simulators, and/or designed a whole new plane. But none of those options are risk-free in terms of safety. Making MCAS more complicated might have made it riskier and harder to test. A new airplane could have come with new problems (like the 787, which has nearly exploded in flight due to battery problems).

I said "pick on" the pilots, not "blame" them. There were a lot of bad things that added up. In the case of the Lion Air flight, the maintenance staff signed off on the plane even though they were aware the angle-of-attack sensors were completely broken, which had nearly caused a crash on the previous flight. The previous flights' pilots also either didn't report this incident, or their report was disregarded. Then when the emergency occurred, the pilots didn't know what to do. There are many reasons that that any plane's trim system could have malfunctioned, and the black box data suggests the pilots would have been unable to manage any of them. So the plane was taking off in an non-airworthy state with pilots who didn't know how to deal with a common system failure and weren't told that a system had just malfunctioned hours previously on this exact aircraft. The MCAS failure was a match thrown into a kindling box of bad circumstances.