Then the question should be; are we holding Russia, Israel and Ukraine to the same standards at Hamas?
Even that is a weird question because Hamas is not a country. It's a terrorist organisation.
I don't get the point you're trying to make here. I feel like you just want to hate on Ukraine. You are arguing that cluster bombs are illegal, which they are in most part of the world but not in Ukraine, and then crying about Ukraine using it, while blantly ignoring the human rights violations and war crimes committed. Things that are actually illegal internationally.
Check that link you posted. It's only illegal in signatory countries. That's how international law works. You can call it morally wrong, but if you call it illegal that's just false unfortunately.