How much damage has those Russian and Iranian built rockets done in Israel? How many tanks do Hamas have? How many fighter jets do Hamas have? How many nuclear weapons do Hamas have?
The fact is, Hamas is a product of being a military in a territory that is subject to blockade by Israel. You can say Israel left Gaza in [insert year], but the fact of the matter is that a blockade has been there up to now.
And so if Hamas was a democratically elected government of Gaza, with the opportunity of becoming a 'Singapore' of the Middle East and having full agency (as Israel claims), why is it outside the bounds of reasonableness that they do acquire weapons from Russia and Iran, just like any other country in the world does for their own military needs?