The central issue with invoking the Emergency Act is twofold: First, it is a step too far in consolidating state power against dissenting citizens. Second, police already had the tools they needed to deal with the occupation in Ottawa but chose not to. If the police had exhausted all their options first (which are routinely used against Indigenous and climate change protestors) then Trudeau may have a case. This did not happen.
If we were to wonder about an alternate future in which the Conservative Party of Canada was in power during the current pandemic, we wouldn't need to use our imaginations to understand how they would govern. The track record of Conservatives currently in power speaks for itself.