The icj despite all the evidences proving it still decided to not say definitely that there is a genocide.
Because they do not have the evidence necessary to rule that way. Mostly, yes, because Israel is rather uncooperative, and the ICJ can't just raid Netanyahu's office.
With their ruling no country has obligation to do their best to stop israel occupation and agression.
All countries have that obligation no matter what the ICJ rules.
Do you want the genocide to be admited a decade after it happened just like with the bostnian genocide declared as such after 12 years?
This is not about "admitting", or "strongly suspecting", or "preponderance of evidence", but "beyond reasonable doubt". Proof should only be declared when it's actually bullet-proof.
As said: Otherwise, you leave an attack surface for genocide deniers, they'll spend the next 1000 years talking about "The antisemitic conspiracy that managed to frame Israel for genocide, here, have a look, they suspended due process to come to that conclusion". Don't play into the hands of those assclowns.