From what I’ve gathered it’s mostly municipal incompetence.
Ottawa police let them get entrenched, going so far as to offer use of a city owned baseball stadium parking lot which rapidly became a logistics base. They assumed protestors would park their rigs and travel in to the city to protest in a traditional way.
Instead protestors set up camp on downtown streets in a weekend and the local police had no idea what to do. By then it was too late. There were over 8000 people present the first weekend.
Police stated that attempts at enforcement would not be safe, probably because police felt just as threatened as residents did and they simply didn’t have the numbers to break it up.
They then shifted their plan to “maybe they’ll get tired” for two weeks which took us right up to the emergency act being enacted and police being able to muster the numbers required to disperse the protest.
At the provincial level, well, it’s an election year and the premier has an awful lot of voters who agree with the protestors, so he did his tried and true crisis management technique of hiding in a dark room.