Doesn't it seem likely that tax treatment has more to do with this than benefits? People are reading this like YC isn't investing in companies HQ'd in Canada, but there's no evidence of that! I look at a set {US, Singapore, Cayman} and what I think is "this is about taxes". Maybe especially tricky for YC since such a huge fraction of their portcos are pre-revenue.
The key question is whether they make non-US-ians move to the Valley to participate. Or, rephrasing, leave their home country to move to whichever piece of YC is cutting the check.