I preordered my S10+ with Telus as they were the only provider giving the free buds so to correct your post, no sorry Canada was NOT excluded.
Both Telus and Koodo (Telus subsidary) had this offer.
I totally understand, it's really frustrating when our neighbours down south always seem to get more bang for their buck...
Although as @Habsfan and @SnowCat19 mentioned, the Galaxy Buds offer was carrier-specific in Canada. It's not much compared to the US deals, but at least it's something!