No. This is a major issue, because it demonstrates that the safety protections which have been built into the industry can actually fail on such a basic level. There has been an enormous amount of work to try to make sure that Airplanes never miss critical components of their structure. Failing to install a bolt isn't one mistake it is dozens of mistakes which need to have happened and which show that the overall mistake rate has to be high.
If the door at failed at a different point, if the seating had been different, then there would have been deaths.