The article clearly says that it is for the US but I still can not think of a reason why that would be valid for US and not Europe for example You misread the

The article clearly says that it is for the US but I still can not think of a reason why that would be valid for US and not Europe for example You misread the jokey intro I think, which goes on to say it applies essentially everywhere in secondary effects; it makes no claim about the direct value of long term mortgages elsewhere except by implication that in similar systems generally they are a bad idea.