Road traffic kills over a million people every year, many of them due to various technical and design flaws. People just tolerate those deaths far better than deaths from plane crashes.
If you want to liken the 737 MAX’s failures to road traffic, you have to ask yourself if there’d be broad acceptance of shoddily built, fault-intolerant bridges and freeways. Moreover, would that acceptance be greater or lesser if the public knew that engineers believed their designs were flawed?