Passenger does not appear to be entitled to denied boarding compensation. Let me explain...

Per Rule 70 Part B of the Air Canada International Tariff:
The passenger must be available for boarding at the boarding gate at least 15 minutes (exception for Tel-Aviv 60 minutes and Casablanca 30 minutes, for domestic flights and flights to/from the U.S.: 15 minutes) prior to scheduled departure time of the flight on which he/she holds a reservation.

According to vroom's post from above:
Yesterday's AC 7408 landed 45 minutes late at 20:13, schedule departure time for AC 46 was 20:35. So this is probably what happened.

<I assume landed means arrival time at gate>

I don't know about YYZ, is it possible to get from a USA inbound flight to the departure gate of an International outbound within 7min?
Don't forget, on the Air Georgian CRJ inbounds, it takes about 2min to open the aircraft door, bridge, and put the mobile bridge adapter on.
So that brings us to 5min.
Was the passenger in the first row?
Now we are talking less than 5min.
Again, unless you are Usain Bolt and there is no congestion in the terminal blocking you, it is highly unlikely that you could make it to the international departing gate by 20:20 given these circumstances.

So when you arrived at the gate, the question becomes, as a gesture of goodwill, does the airline put you back on the flight? If you have checked luggage, not likely, as this will create a PAWOB and then the airline is liable. Better to deny boarding in accordance with the tariff without compensation and rebook the customer.