It’s not - Israel’s army is among the small set of armies that continues to use illegal munitions (I recall they were using cluster bombs a few years ago).
I am unclear why they feel it necessary, but that’s how their army operates (not helped by their current nationalist PM) :-/
The geneva convention only covers militaries not police forces. Regardless "international law" is a bit of a misnomer. It exists only at the tolerance of sovereigns who can and do ignore it whenever it suits them.
> exploding bullets that are causing severe injuries reported today and on other days
How is this okay?!