Taking hostages of any kind is illegal under international law and Hamas bears full legal responsibility for any harm under the Geneva Conventions. If Hamas can’t keep the hostages safe they should have surrendered them.
Further, under article 58 of the 1949 Convention, both parties are responsible for taking measures to allow innocent civilians to reach safety. In the case of Rafah that would mean allowing them to move to the north or seek safety in Egypt. Hamas doesn’t feel it owes its civilians anything – to them they are just potential martyrs.
Recent prices to allow Gazans to migrate temporarily into Egypt is about $5K per adult, $2K per child where most of the money goes to Bedouin smugglers and Hamas. Now that Israel has taken the Gaza side of the Rafah crossing from Hamas these costs should go down.
How much have you contributed? My bet, as evident from your posts, zero.