LTP's point is a good one; best practice must surely be that controllers only give avoiding action TURNS rather than level changes. Whether or not the controller in question felt that this was an avoiding action scenario is arguable.
As for the chain of events [and although I'm a controller myself] I have to say that I disagree that the controller was entirely free from blame. He was one of the last links in "the chain", and could have told the engineers to get lost. I fully accept that he should never have been placed in that position to start with, but he must shoulder at least a modicum of responsibility as he chose to continue providing two different services singlehandedly even knowing that the system was seriously degraded.
I have been through the "then you'll be unplugged!" scenario, it leaves a very bad taste in your mouth - bottom line is, however, it's my licence and my responsibility and I'll call it as I see it.