The relevant distinction is that Abe was assassinated by a Japanese national, not by a foreign national, so in this instance there will be no catalyst for escalation and payback.
Gavrilo Princip wasn't a foreign national, he was Bosnian which was then (at his birth and in 1914) ruled by Austria-Hungary, one of the many ethnic groups that composed the empire. He was part of a Bosnian revolutionary group that was helped/sponsored/trained by Serbia, so there's a foreign connection, but he wasn't a foreigner.
