Not quite - you are meant to respond in a proportional way and minimise civilian casualties. It sucks, but civilians die in war and this must be minimal.

Level the whole building - non proportional, didn’t minimize casualties, probably a war crime (as it is a military target it may be considered acceptable).

Blockades to remove hamas strength and stop aid supplies that aren’t getting to civilians anyway- proportional and minimises as opposed to what else can be done.

Restricting resources then invasion - legal to remove a threat, proportional, minimize casualties.

Interestingly this is the exact same response a police force will do if someone blockades themselves inside a building with human shields and takes pot shots at everyone walking past - starve, remove strength and resources, get as many hostages out as you can then invade it.

Using civilians as a human shield in a state-state conflict is a war crime, however if hamas is considered a terrorist organization rather than a state it is no longer war and not technically a war crime. I believe other laws come into play however, its been a while.