Found guilty to provide adequate humanitarian aid? No, they were not found guilty of anything. The ICJ denied South Africa's request for a preliminary injunction and instead told Israel to submit a report and to be sure to provide aid. It literally didn't order Israel to do anything it wasn't already doing. Not sure where you got the idea that Israel had been found guilty of something by anyone.
Israel does allow journalists into Gaza in groups. But their reasoning is not secret and not unreasonable.