This is exactly right. The passenger profile for KIN is unique amongst amongst AC destinations, with the possible exception of PAP, which I have little experience with.

MBJ flights have a mix of “friends and family” traffic and resort-bound tourists so baggage loads are not incredibly heavy. Your average week-long Sandals visitor is packing a few swimsuits and some personal items… not much more. Helps offset the pax laden down with gifts for family.

The KIN flight is pretty much 100% “friends and family” so that extra bag is usually not a bag at all but a massive flat screen TV, a set of tires wrapped in heavy duty cellophane or some manner of automotive part or household appliance. The Jamaican diaspora in Canada as well as a huge temp worker contingent makes for a steady flow of goods bound for friends and family (or the resale market) that are cheaper to obtain here and transport vs. local procurement.

You might ask, “how do they get all that stuff on the plane?”… quite frequently, they don’t.

There are other ethnic communities in Canada that tend to pack heavy, but they tend to hail from long-haul markets served by widebody aircraft that have significantly more baggage capacity. If the word “balikbayan” means anything to you, you know what I mean.

Operationally and economically, the KIN flight is in a category by itself so a KIN-specific baggage policy is not shocking. A high excess fee makes additional baggage possible but impractical or in some cases unprofitable.