This is mis-stating (I suspect deliberately) the situation under Canadian law. They weren't "stripped" of Canadian citizenship (as can happen to war criminals who lie on their citizenship applications); rather, it was discovered that they had never been Canadian citizens in the first place. Their parents lied to them and told them that they were Canadians; but the fact that they were harmed by their parents' fraud is not a reason for the fraud to be made reality.
On the other hand, the Canadian government does seem to be wrong when it comes to blaming them for the circumstances and annulling Alex's student visa. The fact that have they lived in Canada and identify as Canadian seems like strong considerations in support of an application for a visa or even permanent residence; the fact that they were tricked into thinking that they were Canadian once doesn't mean that they shouldn't have the opportunity to truly become Canadian.