The Video Description mentions his thoughts:

Norman Finkelstein: Well, my first reaction is that you have to have the facts and make a careful evaluation on the basis of the facts. When I first read about it this morning, I thought it had occurred at the Israeli consulate. And I assumed it was a Palestinian who had committed the action. And my first reaction was to remember the [Polish Jewish] fellow Herschel Grynszpan, who assassinated the second-level diplomat in the German legation in Paris in 1938.

He reacted in sheer horror at what was being done to the Jews. And he did an act. Of course, the Germans called it an act of terrorism, and that’s what triggered Kristallnacht. I’m not aware of any [historians] who condemned him for the act, even though you could say it was not a very smart thing to do because it triggered Kristallnacht.

So that was my initial reaction. But then that turned out to be wrong because of two things. It didn’t occur in the Israeli consulate. It occurred in front of a Jewish museum in Washington. And secondly, it’s unclear at this point whether the alleged perpetrator was even aware that these two people worked in the Israeli consulate. So that throws a large number of variables into the equation. There seems to be this big disconnect between a sophisticated manifesto and a fellow just going randomly in front of a Jewish museum in Washington and attempting to assassinate two people who presumably he thought were Jewish.

So everything remains foggy now. I would say for me, the bottom line is it could have been a nutty guy. That’s always possible. It could be a smart guy with a crazy project. It could be a crazy guy with a crazy project.