Freedom from religion is already a Charter right as the SCOC made clear in one of its first Charter rulings in 1985 in R. v. Big M Drug Mart Ltd., [1985] 1 S.C.R. 295:

"The values that underlie our political and philosophic traditions demand that every individual be free to hold and to manifest whatever beliefs and opinions his or her conscience dictates, provided 'inter alia' only that such manifestations do not injure his or her neighbours or their parallel rights to hold and manifest beliefs and opinions of their own. Religious belief and practice are historically prototypical and, in many ways, paradigmatic of conscientiously‑held beliefs and manifestations and are therefore protected by the Charter . Equally protected, and for the same reasons, are expressions and manifestations of religious non‑belief and refusals to participate in religious practice.'

Ans subsequent SCOC decisions have affirmed the right to be free from religion.