There's a difference between the measurement "how much homework a student have" and the measurement "how much parents help with children's homework". The article is about the latter, while the GP discusses the former. I'm pretty sure Finnish students have homework.

I also think the "poorer countries" is a red herring (e.g. Singapore scores quite highly on the list), I think it's more about cultural differences and competition about a much more limited number of places for higher education.

My own (very limited) experience with the education systems in several Asian countries is that the focus is more on feeding students facts. Whereas the education in the Nordic countries generally focus more on learning how to solve problems, either by yourself or in groups.