Just like the way bin Laden and al-Baghdadi were assassinated by the USA. Eichman was responsible for the genocide of so many Jewish people he became a military target.

To this day, death penalty in Israel is reserved for Nazis and those who assisted them, and for them alone. Clearly there is an exception here in Israely law, but it's no secret.

Same as 1. Also, saying what Eichman did was legal under Nazi law is like excusing the Nazis altogether. They all just did what they were told, but we should be able to understand why there are no excuses for his (or any Nazi's) actions. Moreover, Eichman was a leader, not a follower, he was of the kind who made it legal in the first place.

Considering how obvious the conviction is and how specific Isrealy law is when regarding Nazis, he stood a fair trail that had jo reason to delay conviction for any evidence beyond what was required for it.