It's not whether it's devastating to people today. It's about the fairy tales your kids get told when they're growing up. And grandparent's point wasn't that

It's not whether it's devastating to people today. It's about the fairy tales your kids get told when they're growing up. And grandparent's point wasn't that Canadian's don't have a cultural heritage of invasions and battles, but rather that the Mongol invasion was somewhat different from most of the things going on in Western Europe (e.g. almost all major cities were sacked; casualties were at levels not to be seen in Western Europe until World War 2) and had widespread and long-ranging effects on society that made it qualitatively different from Western Europe. Second paragraph of the "Influence of the Mongol invasion on Rus' society" section of the cited Wikipedia article is relevant here.