You read the part where they say things are not really comparable because different nations use different definitions, right? E.g. if you scroll in the article

You read the part where they say things are not really comparable because different nations use different definitions, right? E.g. if you scroll in the article you will find that Germany reports as homeless: "Living temporarily with family and friends due to lack of housing", "Living in institutions" "Living in institutions" is clarified as: "Including people who stay longer than needed in health institutions needed due to lack of housing; and people in penal institutions with no housing available prior to release". The US does not count these categories. Now, it would be interesting to see how the numbers would change if the US actually counted all the millennials who moved back in with their parents because they could not find an affordable place, and all the prisoners and parolees who stay with relatives.