My understanding if you read the Israeli news articles is that the justification is that the car was going fast:

https://www.timesofisrael.com/israeli-forces-kill-west-bank-...

Given that the IDF involved were undercover agents (according to the reports), it seems unlikely that this family knew that driving fast would get them killed.

Indeed. Often one of the key details omitted is that Israel has been illegally occupying the west bank since 1967 as part of an apartheid regime.

The BBC had a literal Israeli officer as the head of their Middle East department. https://www.middleeasteye.net/news/high-court-rules-favour-j...