Was helping a co-worker book a YYZ-GRU rt in J with AC on Aeroplan and the total charge was only CAD $52.60. I recall someone state it is because the gov over their regulate it. Hence you do a YQR-YYZ-GRU on AC metal on one of your leg.
This is not correct. On AC there is a YQ of $250 each way if originating from Canada. Thus if outbound originates from Canada, either or both legs will incur the fuel surcharge if travelling with AC. I've paid it many times (including recently) due to availability only being with AC on the dates I wanted and for the advantage of having a direct flight to YYZ.
The only way to avoid YQ on this route is by booking the travel originating from Brazil to Canada (e.g. GRU/YYZ/GRU) which are not going to help most North Americans out. That is indeed due to legislation within Brazil.