Granted, tacking them all at the end isn't necessarily good, but at least the user will see them, and timestamp indicators can help make sense of it.
And I don't even see how placing them chronologically would be particularly useful - given a netsplit there's not gonna be any relation between the previously-present and delayed-received messages at that time interval anyway, you're just interleaving two entirely different discussions for no reason. (ok maybe there can be some unidirectional delay where it could maybe be useful, idk)