The Supreme Court of Canada has the obligation to follow the law as written...and the law is quite clear on consent. The majority of the court obviously interpreted this section as saying an unconscious person cannot consent to what is being done to them...and what alternative did the Justices have? Is an unconscious person capable of removing consent? No.
273.1 (1) Subject to subsection (2) and subsection 265(3), “consent” means, for the purposes of sections 271, 272 and 273, the voluntary agreement of the complainant to engage in the sexual activity in question.
(2) No consent is obtained, for the purposes of sections 271, 272 and 273, where
(a) the agreement is expressed by the words or conduct of a person other than the complainant;
(b) the complainant is incapable of consenting to the activity;