The reduction from 3 to 2 operators, the acceptance of long breaks when there were two operators so there was only 1 in the room for a prolonged period of time, the pressure to cut costs, the lack of understanding of what systems were down during the upgrade, the surprising loss of hard lines without a tested alternative, the lack of a supervisor concentrating on the upgrades at the time, the lack of appropriate assessment of the risks.
Most of it seems to come down to trying to cut costs and reduce conflict with the staff (the acceptance of the “long breaks” overnight)
None of that lands on the overworked controller trying to do 3 jobs
You're simply misreading it, ATC refers to the specific person(s) responsible at the time.
Perhaps you're tripping over "responsible", it helps to read it as "if you, future person, are in this situation, consider how you could avoid a similar accident, given your position in the system".
It does not necessarily mean "this person is incompetent", or "this person is criminally liable". That's outside the scope of such reports.
If it didn't mean that, then someone in the ATC chair in the exact situation tomorrow would need to helplessly watch the same tragedy play out in front of their eyes, would they not? Even if they'd have the benefit of hindsight in having read this report.
After all they'd be a powerless puppet strung along by systemic causes.
Most of it seems to come down to trying to cut costs and reduce conflict with the staff (the acceptance of the “long breaks” overnight)
None of that lands on the overworked controller trying to do 3 jobs