I just don't see the evidence that there's a significant difference in price between Canada and Bermuda cruises on comparable ships at the same time of year.
In August, RCI's Enchantment of the Seas is sailing a Canada itnerary out of Boston. The lowest category inside stateroom on Enchantment's August 30th sailing is going for $719/pp.
The lowest category inside stateroom on Voyager of the Sea's August 21st sailing from Bayonne to Bermuda is going for $799/pp.
This is a difference of only $80/pp, plus you're booked on the Voyager, a much larger and typically, more expensive, ship.
Differences in cruise pricing seem to be based, for the most part, on time of year and on the ship, not on the destination.