What should they have done, run away and left their families and neighbours to the tender mercies of the Israeli army

Accepted practice is to evacuate civilians from military installations when hostilities are imminent.

to be defending the killing of "hostages"
However distasteful, it is accepted that civilian casualties will be incurred when one side uses them as living sandbags.
The crime is theirs.
The other side must give prior warning, as Israel did, (negating the advantage of surprise) and must try to minimise civilian casualties.
UN did not find Israel to have acted illegally.
The rockets were declared illegal.

On Bloody Sunday a couple of soldiers fired on the demonstrators.
They acted without orders.
They should have face prosecution as happened in subsequent incidents