It goes back to my point about the idea that if you strip citizenship from somebody and send them to another country where they hold citizenship, somehow they belong more to that country.
When you're talking about people who are born and raised in Canada, there are many people in Canada who are born and raised here who commit terrible acts for which they have been and deserve to be punished, but they are a product of Canada. Whether somebody acquires what are considered to be disloyal views to Canada, they nevertheless are born and raised in and are a product of Canada. They don't belong to some other country more just because they happen to also hold that citizenship.
Again, it is arbitrary and not logical to assume that, for example, Colonel Williams belongs more to Britain than he does to Canada, or that somebody who is born and raised in Canada and happens to be a dual national and who commits what is considered to be a terrorist act more broadly, not specifically against Canada but generally, somehow belongs more to that other country of which he or she is a citizen.