What he applied is EGPWS terrain avoidance procedure in normal law where you slam the thrust and keep back stick because stall protection will take care.
A perfect example of applying the wrong SOP. But why did he do it? Perhaps it was because he wasn't trained to think, didn't think, or even just didn't understand aerodynamics. Perhaps it was fear, perhaps it was lack of training, or perhaps it was a lack of aptitude. Or perhaps it was a combination of all of those things.
The thing is I often see the blind application of SOP's without any thought, along with blind faith in the absolute reliability of automation. Things have been learnt by rote & are applied by rote. I don't know if it is a training issue or an aptitude issue, or perhaps a bit of both. Perhaps laziness & lack of professional discipline, thought & study are part of the issue as well.
Whatever the reasons, if the industry continues to move down the path it is on & pilots forget how to be pilots & lose basic flying skills, there will continue to be an increasing number of accidents. People will continue to ask "why did he/she do that?"