China officially recognizes the state of Palestine.
The Isreali supreme court itself has determined that Gaza is not Isreali territory.
However, situations like this, in which rhetoric and de jure policy conflict with de facto reality, open one up to others taking the fiction at face value. And what do you do then? Can't deny it without causing other problems. So now this may be regarded as an international matter because Gaza "isn't part of Israel".
An Israeli court can say what it wants, but can't have it both ways.
The supreme court has jurisdiction over actions taken by the Isreali government, regardless of where those actions take place.