Maybe because it is a (congested) road, not a parking lot.
Dozens upon dozens, if not more than a hundred homes line the east side of this residential road and many, if not the majority of which have no parking space on their property and like most of urban, inner-city, residential neighborhoods in Toronto, the property owners are allowed permitted parking on their residential road.
Also, there is no NO PARKING on the west side of this residential road Parkside Drive from Bloor down to the lake.
This is a residential road, NOT a road artery to be abused by those rollicking and racing through it.
What defines a successful city is its people, neighborhoods and communities, NOT free and open, wide and fast, scofflaw ridden, lawless roadways.