Brendan never made it out to be "black and white." Brendan merely showed that the principle is flawed.
Understand this, Brendan isn't using that as a complete refutation of the entire argument, he is attacking that link of the argument - rendering it invalid by the principle stated by Eriny.
Here is a rebuttal to your analogy:
But there ARE conditions on Y. And it is these conditions that Brendan fails to see. By making it a black and white 'X' and 'Y' you remove all mitigating W's, Z's, the odd M or L and sometimes an N that influence the 'Y'! These W, Z, M, L and N's are the universal declaration of human rights, the people that make up the regulatory bodies etc. By disregarding that process, you TRIVIALISE the decision and take away the multi-dimensionality of the argument.
Firstly, 'X' and 'Y' are totally different things. 'X' was an agency, and 'Y' was an action. Even if Y is a function of all those other variables, the principle still blatantly said: if X says: do Y (whatever the result is, as a result of computing all of the other factors), do it.
You can defend your own principle,
enwiabe, without trying to defend
Eriny's, because hers is probably indefensible. Personally, I wouldn't have pointed it out because it becomes a mainly semantic argument, with little enlightenment and progress, but it is still important to attack it, based on principle, I guess.