There may be tariffs in place, or the company just chooses to charge more in Canada because conditions lead them to think they can charge more.
It can go both ways though. I was going to buy an LG laptop once, which isn't sold in the US because LG makes some laptops for an American company and agreed to no competition. Anyway, I found it on a Canadian site which would ship to the US and had a site for US customers and US dollars. The US dollar price was more expensive that n the Canadian dollar price with the exchange: same seller, same product.
The funny thing was, you could order from the Canadian site and have it shipped to the US, thus getting the cheaper price.