They worked on the technical bits that they liked, created a terrible UX that sounds user-hostile, and then shocked-pikachu discovered that their jobs got cut in half.
The decision to whisk UX duties to a team miles away was moronic, of course. But that was a reaction to the bad acts this team did - to their customers, to the business, and to themselves.
Why do we expect that skilled SEs are also skilled UX designers? As everything, design requires training. The problem seemed to be such people trained in design were missing from the R&D team, which sounds like management's fault rather than the engineers' in the first place. Then, the management, while correctly identified the lack of design skills, instead of strengthening their R&D team with that missing talent, they put designers in a different group, creating a different set of issues within the company. Seems a case for an overall bad management in my eyes.
But everyone needs some of both - the most purely technical engineer still needs the personal judgment to hit dates that matter, show up when others need them, and avoid overinvesting in purely play activities.
In this case, better managers would help but honestly any experienced engineer would know that constant customer complaints mean that something is going to change.
Sometimes that's true. Sometimes it isn't, and the bad UX is the seed that leads to a terrible destructive management overreaction.
Should an engineer be able to tell the difference? In some companies, I think that's a reasonable expectation, but in other companies, engineers are cordoned off and told what to do.
I'm reading the same article that others are, so I don't know. But I do see a lot of engineers get surprised in a way that could be prevented by just a bit of proactive thinking.