> Court deciding earlier in a 2-1 decision that Palestine is a state, the PA is the legitimate government of Palestine, and that Gaza is territory under its jurisdiction.

I think you are overstating it. They made a provisional decision, but just for the purpose of if the investigation can go forward. The decision does not decide whether or not palestine is a state in general, and if this ever goes to trial the defendants can still challenge this decision.

This case was not filed by any country, it was directly filed by Karim Khan, an employee of the ICC.

The court that requires a country to file is the ICJ. Iran is already a signatory to the ICJ and there is nothing that would legally prevent them from filing a case if they wanted to.

I was also curious about parent's claim so I did some searching of my own. The claim is from a report published a few days ago called 'South Africa, Hamas, Iran, and Qatar: The Hijacking of the ANC and the International Court of Justice':

https://isgap.org/follow-the-money/

Its author, the Institute for the Study of Global Antisemitism and Policy, is ostensibly American, although I can find no indication of its incorporation in the USA. The Israeli government is the largest donor to the organization according to 'The Forward', which is a newspaper incorporated as a non-profit charity in the USA.