Eyewitnesses tell Asharq that beside the disguised troops, other special forces snuck into the Nuseirat camp inside an aid truck. The IDF has denied using humanitarian transports for the operation.
From the link you posted, it seems this would still be a war crime if it’s true, unless I’m misinterpreting the text:
Ruses of war are permitted. Warships and auxiliary vessels, however, are prohibited from launching an attack whilst flying a false flag and at all times from actively simulating the status of protected vessels such as hospitals ships, small coastal rescue craft or medical transports.
I assume the aid truck they were using would qualify as an “auxiliary vessel”, and they were using it to impersonate “medical transport”.