Jeez, rudestuff, I don't think it's a case of valid excuses or not - sounds like he was faced with a split-second decision, the kind none of us want to have to make, and did very well.
Bottoming the collective is hopefully an ingrained response, and I wouldn't think that from 50 ft with an engine failure there'd be heaps of time to go 'hmm, that rotor rpm is pretty high for my collective position, best get that checked after landing'!