Actually, they do accuse Israel of it (that is why it’s deemed possible that they are committing genocide), but have not ruled for or against this yet.

A judge or a court cannot accuse people of a crime in a common law type of court in the middle of a case, that’s the prosecutor’s role which is led by South Africa. The court can issue injunctions which is an order to not do those criminal things, but only later will they issue a decision determing guilt.