It's actually something they can't stand because it's so sample size based and inmeasurable. It's really anti stat geek in every way, shape or form.
In fact your idea of what clutch is is more in tune with what stat geeks think, while others seem to attribute clutch to something they hear a lot. David Ortiz is really clutch because he had a good player series. All be damned if his stats in big playoff games reflect his stats in all normal games are about the same but dammit remember in 2004... he's clutch.
LeBron has some bad fourth quarters and he instantly becomes un-clutch from the major media despite the fact overwhelming evidence shows he's just as good of a player in those situations.
There's also fluctuating clutch the major media tends to use as well. LeBron dominated the ECF, absolutely dominated the Bulls and was the reason they beat the Bulls. Then in the Finals he had a few bad games, do you think those were treated equally? Of course not. He instantly became un-clutch and couldn't get it done in the big game, despite getting it done in a ton of big games the entire year.