> Isn’t this because they are non-members?
No. For non-members it is assumed that they by default ask the ICC to not investigate any human rights crimes either involving their state, or on their soil. Which the ICC then has to respect ...
Or that WAS the case until last year. In the middle of their existing court case against Israel it became clear that Israel requested ICC drop the case on their territory, and of course Palestine has neither borders nor are they a member of the ICC (despite Palestine signing the Rome accords to immediately afterwards start screaming on TV that they wouldn't respect them as they relate to Palestinians themselves), and therefore there were no grounds for the case. So South Africa, amidst allegations of Qatarese bribery, was allowed to bring a claim, and that South Africa has now twice helped people convicted at the ICC escape ICC justice did not negate that (they helped Bashar Al-Assad, and Putin)
So then the ICC modified their own statutes, which they're not allowed to do, so that the particular kind of non-member that Palestine is, would be allowed to put disputed territory as valid territory retroactively for such complaints (because despite how the press presents it, Palestine's claims relate to the treatment of Palestinian prisoners, specifically underage ones, on Israeli soil, NOT about what happened in Gaza. You see, the court has accepted an argument that since neither Hamas nor the PA allow investigators or journalists on their soil, claims there cannot reasonably be the basis for any conviction)
In other words, the court allowed what is effectively Hamas (not the PA) to enter Tel Aviv as territory for this court case.
You see, this is about Hamas scoring a PR victory. The idea that Hamas, through Qatar, via South Africa, is worried about the treatment of a West Bank resident Palestinian boy is utterly absurd. The only thing they care about is that it is an argument they might win, at which point the papers will be full of "Israel convicted at ICC for human rights abuses". This is the same Hamas that has mounted a suicide vest on an unwilling underage girl who was being treated in Israel for cancer, forced her to try to cross the Israeli border, and blew her to pieces when she tried to get help from the border guards, you see, THAT organization, is really worried about whether children who killed someone people get to see their parents sufficiently often in prison ...
Yes, Hamas is a party to the Rome statute (they agreed to respect it so they could partake in elections, elections, I might add, that ended with Hamas executing election officials in the emergency ward of a Gazan hospital) and plenty of other treaties at the UN. Including treaties that they'll prevent any and all terror attacks against civilians ... Meanwhile they AND the PA, pay Palestinians a monthly pension based on how badly they hurt Jews [1] (sorry, this organization that signed treaties to arrest any terrorists they know of "has stopped doing that" 4 months ago. They promise. Needless to say, the payments continue)
Obviously this ICC rule change is insanity and will lead to disaster, and they'll retract the rule when it is used by anyone else, for example, when Kurds enter a claim about abuse in Ankara for example, Iran or Iraq, or Druze against Syria, or ...
And while this is the most egregious example of abusing the ICC, it is far from the only one. There's a similar conflict with the US. The problem with the ICC is really quite simple: a lot of signatories to the Rome statute have zero intention to respect any court decisions made by the ICC, and the ICC allows states to openly defy their treaty obligations without any consequences. The US and Israel, when they realized they didn't either, publicly withdrew so they'd remain honest. South Africa, Mongolia, Palestine, Hungary and others just started violating the treaties they agreed to without withdrawing.
When push comes to shove, a LOT of nations want war, but can't do it, or can't win it, and they see the ICC itself as a weapon of war. A weapon against "the international order" (ie. what the security council represents). The ICC lets them.
> How does that work? Who sets the statutes if the ICC itself cannot modify them?
Oh it is an international treaty. So actually modifying the statutes would be a prolonged process involving all existing parties at the UN.
However, the ICC also publishes statutes on their website, which they modify without considering the correct process.
That, they can do. Nobody stops them.
[1] https://en.wikipedia.org/wiki/Palestinian_Authority_Martyrs_...