Yes, as written, the grounds for revoking citizenship based on acts committed after becoming a citizen apply regardless of how citizenship was acquired, and thus apply to those who are a citizen by birth as well as naturalized citizens.
Whether or not this is constitutionally valid is still undecided despite Justice Rennie's decision in the Galati challenge. On its face, it appears that Justice Rennie ruled this is not unconstitutional. But since he ruled there was no justiciable case to rule on, I think his ruling on the constitutionality of this was mere dicta.
There is, however, a distinction between those who have only Canadian citizenship and those who have citizenship in another country in addition to Canadian citizenship (typically referred to as "dual citizens"), the additional grounds for revocation only applying to the latter. As a practical matter this group largely consists of naturalized citizens. So the practical impact of the law is that it disproportionately applies to naturalized citizens.
The whole "classes" of citizenship discussion is more rhetorical than substantive. The Charter and Constitutional rights apply to all citizens equally. But beyond that, the law is more about differences and lawful forms of discrimination. There are, for example, particular provisions of law which allow Passport Canada to refuse issuing a Canadian passport to some Canadian citizens (the application of this in practice appears to have expanded significantly in recent years), and courts have ruled that a citizen's mobility rights as protected by the Charter are not infringed by the denial of a passport. And of course, the mobility of some citizens is dramatically curtailed, such as those who are imprisoned for crimes. This is legitimate discrimination and restriction. The fact that the law creates these distinctions, and provides for such disparate treatment of Canadian citizens does not create different classes of citizenship.
Note for example that a huge lynchpin in Justice Rennie's decision, in the Galati challenge to Bill C-24, is that citizenship derives from statute, not from the Constitution or the Charter. "Jus soli," for example, in Justice Rennie's view and ruling, has been replaced by statute. I am not sure this will stand up in further appeals, or if otherwise brought before the courts in another matter, but for now it is an official decision . . . and it might be noted that earlier this month Justice Rennie got a big promotion and he now sits on the Federal Court of Appeals.
