Citizens != Their Government != The State
This is a fundamental proposition, even in a semi-functional democracy where the citizens elect the government.
I'm not any sort of expert in the laws of Canada, but having tourists come into the country and spend money, buy goods, form interpersonal relationships, and otherwise not be levying war against Ottawa nor the several provinces, that does not sound like any sort of definition of treason, whether in law or in casual usage of that word.
American tourists to Canada are explicitly rejecting spending that same money domestically at American tourist attractions, and are going to Canada to spend it instead. In times where the USA is battering its northern neighbor, I feel like the visiting tourists are coming as allies, not enemies.
But I defer to Canadians about how they feel, and pass no judgement from here in California.
Assuming this is in the USA, I want to note that there are many other available jobs in the protective services occupation, that can be public or private sector, that face the general public (or not), and that don't have any particular positive or negative connotation attached to the job, even after hours.
The Bureau of Labor Statistics (BLS) has a fantastic reference for available occupations:
https://www.bls.gov/ooh/protective-service/home.htm