Readers would do well to remember this also applies to all the people who were 100% sure it was MCAS related before the wreckage even stopped smoldering.
Given the obvious similarities between the two incidents (same phase of flight, same apparent pitch control problems, known issue that would result in that behavior, etc), I don't think it was unreasonable for people to point out the likely connection.
I am pretty sure any mistaken criticism of Boeing will be swiftly responded to and corrected at HN or elsewhere by Boeing's PR lackeys.
"First and foremost, our deepest sympathies are with the families and loved ones of those onboard Ethiopian Airlines Flight 302."
and
"Safety is our highest priority as we design, build and support our airplanes."[1]
Yeah, sure! We believe you.
[1] http://www.boeing.com/commercial/737max/737-max-update.page
One of the effects of allocating blame is that large swathes of the general public will "switch off" and not ask questions of their politicians, who in turn apply little pressure to improve or advocate for improved standards (which big business and comfortable institutions see as too much government interference).
I can't recall any such incident where it wasn't implied that the it was the pilots fault, implying incompetence. The fact that most of us may have inherent and often unconscious racial biases (black and white and other actually display the exactly the same biases) just makes this play damage control that much easier.