It would depend on what the guidelines and other requirements say with regards to such warnings. It definitely is not a good impression for Alaska for most people, though.
Right, which is why air crash/incident investigations look at all causes. It would be absolutely the wrong conclusion from this to say "the problem is solely Boeing".
The problem can be Boeing, Alaska Airlines and the regulatory system under which they operate since an intervention at any level here would've prevented the incident: Boeing should be doing their job properly, but Alaska Airlines could've done more then the minimum with a plane displaying persistent pressurization problems, and the regulations shouldn't have allowed them to get an exemption to fly with a persistent issue like this on their records since the mitigation wasn't remotely safe.
