Alternatively, he has a sworn duty to uphold law. When it becomes an attack on a religious institution, do you what you agreed to do. Attending a violent protest is a direct violation of his oath. Fire him.The poor quality video ended just at what appeared to be the officer getting involved in a scuffle. That opens a ton of ethical and legal issues. While police officers should be entitled to the same rights as all Canadians they must recognize that their training and responsibilities holds them to a higher standard.
At some point one has to recognize attendance is no longer appropriate and leave.
"I solemnly swear (affirm) that I will be loyal to Canada, and that I will uphold the Constitution of Canada and that I will, to the best of my ability, preserve the peace, prevent offences and discharge my other duties as (insert name of office) faithfully, impartially and according to law."