If you read through the linked twitter thread it seems like it’s a significant majority too. Obviously this is totally contrary to what Israel has previously claimed.
I also suspect that many of the civilian deaths were caused by the IDF using them as cover, especially at the festival.
In any case, next time someone talks about indiscriminately killing civilians, you can point out that unlike the IDF, Hamas has predominantly and objectively focused on military targets
In conscript armies auto promotion to corporal after a few months is quite common. I know quite a few older people that were conscripted to the South African Army before 1994, and most were corporals or lance corporals.