Citizenship is alienable. It always has been alienable. It is alienable in every other democracy. It is alienable based on the volition of the citizen. They can choose to renounce their citizenship. It is also alienable based on an initiative of the government under enumerated grounds, those enumerated in the Citizenship Act.
Under the current act, the enumerated grounds are essentially if the citizenship was obtained through the commission of fraud, but prior to 1977 another enumerated ground for revocation was an act such as acts of high treason or acts of war against Canada.
It is alienable. It always has been alienable. That only makes sense, since it is predicated, as I say, on a reciprocal loyalty.