If they actually have anything to do with the mandates, then protesting in Ottawa doesn't make any sense.
All of the health and COVID mandate policy is set at the provincial level in Canada, not federally. They should be protesting in Toronto, or other provincial capitals.
However, a good percentage of provincial capitals are currently Conservative governments. So, by deliberatly choosing Ottawa, they're protesting legitimately elected government to force them to step down (despite being democratically elected 6 months ago) and install a new leadership panel made up of the convoy leadership.