I have to agree, what a shocking chart. The obvious mistake to make is leaving IRK on your DME, not IIRK, but this would make you 600' (or so) high. Leaving MCM on when being vectored from the south and descending at 10.2 MCM is, as has been pointed out, miles worse.
I only did 600 hours in the JS32, but I saw this mistake (wrong DME selected on a 2 DME NPA) at least twice. But on our charts for this UK regional airport, we had a height table. And the two DME's had very different names. And we'd always put a NPA into the GPS, as a "backup".
After a very long 6 sector day, the kind of mistakes that I make are the "failing to remember to push one button on the nav equipment" type.
I really hope that if the "cause" of this accident is found to be the incorrect selection of navaids, then the outcry is not "pilot error", but "fatigue" or "15 hour days" or "6 sectors".
I am the master of making mistakes. I am at my most masterful after 6 sectors of practice.
What a tragedy.