By this argument every war since WWII, any act of war, would result in the same.
Nuremberg was at the time specific to the atrocities of WWII. They shocked the conscience of humanity so fiercely that the world demanded harsh and swift accountability.
Today, there are wars started in many corners of the globe. If there is a legitimate claim of genocide, there could be consequences, but neither US or Israel are members of the ICC as I recall. The ICC would be the deciding body and as I understand they only offer suggestions and written legal context. This can hurt a nations goodwill and reputation without question, but ultimately the domestic courts would decide their fate and it would rarely if ever be hanging.
If WWIII begins and nukes start dropping. If post-nuke humanity survives I would expect that capital punishment would be on the table for many. This is not the case today so he is engaging in hyperbole and vexatious language.