What does Uberdude's lengthy and detailed analysis tell us ordinary folk, without our having to do hours and hours of homework on it to tell the wood from the trees?

As he says, whether a move is appropriate depends on the situation - that's a universal truth - so, in this case, what is that situation?

My guess is that the value of black blocking at S14 depends on whether black already has influence over the lower right side, so that the blocking move would work with it to start to form a right-side moyo.

In the game under review, that is not the case: in fact, it's just the opposite: it's white who has a lower right side presence.

To be sure, S14 is kikashi - white has to defend at R15 - but the position after he does so is overall better for white than it was before black blocked, because:
(1) black now has one less forcing move opportunity against the top right corner
(2) black's two stone pillar (R14, S14) is more of a liability than an asset, because the forced response white R15 separates it from the ugly empty triangle Q16,
(3) Q16 is also weakened by white R15
(3) white already "owns" the lower right, negating the influence of the pillar over the right side