When entering Canada the CBSA agent has two questions to ask:
1) do I let this person in Canada or send them on their way?
2) do they have to pay duty/are the brining in something they shouldn't?
A Canadian citizen has an automatic right of entry into Canada. Nobody else does (except the Queen). That means the agent will only care about what you're bringing in.
If you identify as a US citizen then the agent must still concern themselves with whether you should be let into the country.
All that is to say all the other posters are correct
