I can't even bring myself to be mad at him, as he's just another victim of Peter Principle. You could argue that he should have shown some humility and self-awareness by never taking the job in the first place, or should have left of his own accord long time ago, but we know managers never do either. He fancied himself for the challenge, has been failing/failed miserably, and is now expecting to be put out of his misery. I'd argue that this experiment is also hurting his stock and career prospects at this point, in addition to all the damage it has been causing to this club for months.
Levy/board have put all their eggs in Ange basket in the context of this season, and now they can't find a way out because the damage is already done. That's me assuming that they don't see all this as a bump in the road and still somehow fancy the guy as a viable long term option by the way. It wouldn't shock me if they chose this guy as their hill to die on, but it would be hilarious regardless.