I feel sorry for Diana.
There was an issue in the Bake-off tent. One of the bakers found his work had been destroyed through no fault of his own, and with no opportunity to recover from the problem. He reacted badly, and was subsequently eliminated.
The producers of the show proceeded to cut the footage for maximum drama - the teaser for the show had MB noting it was "sort of unacceptable" with an immediate cut to Diana; lots of shots of our arch-villain looking eeevil; the rising tension music immediately before the problem; her comment that "he has his own freezer to use"...
And so there was a reaction. That's hardly surprising - the show was clearly structured to get a reaction, and they got one. Big shock there.
As far as I can see, there was an injustice, and it was at the hands of the judges. There's a precedent for what happens when a contestant is unable to finish a challenge through no fault of his own - two years ago, John cut his finger and was unable to continue; they suspended the elimination and carried on. Well, that's the case here, too - Iain's ice cream was removed from the freezer (probably by mistake), rendering him unable to complete the challenge. He didn't have anything to present to the judges, and it wasn't his fault. (And Paul's assertion that he could have presented his sponge and meringue is wrong - firstly because they were with the melted ice cream, but secondly... does anyone believe he would not have been eliminated had he presented just two of three parts of the challenge?)
(Incidentally, the reason this is not the same as the custard incident from last year is that the problem with the custard didn't prevent those involved from completing the task; the mistake this time did make it impossible to complete - you can't complete a baked alaska without ice cream.)
So, yeah, there's an injustice here. Actually, there are two: Iain's undeserved elimination, but also the villification of Diana for the purposes of good TV. And, frankly, I don't think I care to watch this show any more.
One more thing: Sue Perkins tweeted about the controversy, noting the over-reaction and noting also that it's a show about CAKES. There's just one thing wrong with that, though.
It's not a show about cakes, and it never has been. It's a show about people, specifically the dozen or so contestants in the tent.