From the article:  "If this means that the judge was ruling that until a woman loses consciousness she cannot be said to be “incapable of consent,” then he has made a legal error."

It's based on a 2011 Supreme Court ruling that someone who is extremely intoxicated may not have capacity to consent even though they are still conscious.  That's not, as you argue, trying to "engraft new standards of consent retroactively."  It's suggesting an error in law as it stands.