The lack of documented cases of IDF rape does not mean that it doesn’t happen. There are remarkably few documented cases of rape by US military members; about the only time they come up is when civilian courts investigate and prosecute the cases. When the investigation/prosecution is done by the military, they largely seem to disappear.

I would wager that, if there was a truly independent oversight group that had the power to investigate and prosecute allegations of sexual violence by members of the IDF that you would have a very different picture.