The reason Kono dismisses Candidate A, the sanrensei option, is because the normal follow-up becomes too good for Black. This is as shown in the following diagram, where the placement of the marked Black stone is even better than it would be at A. However, it should be noted that even against the sideways Chinese at A, we have only one example (out of 140) where White plays the sanrensei, so it is clearly the initial surrender of the entire upper side to Black that is the problem, rather than the precise location of the "Chinese" stone.
As it happens, White's responses are not really much different whichever size of sideways Chinese Black plays. Kono's candidate B is also rare against the bigger version, and Kono explains the thinking as follows:
Black could play A (then White B, Black C) here, too, but the omission of the White centre stone on the left side makes White weaker on the left and thus makes Black stronger in the upper left. Black could therefore take the opportunity to jump to 6 on a larger scale, the marked stone being beautifully balanced. In any event, it seems that all pros are very chary of letting Black create a huge sphere of influence at the top so easily.
We now turn to the genuine candidates.