Hamas's killing resources and terror infrastructure must be destroyed.
Should we not have bombed Germany to defeat Hitler? Do you know how many innocent German civilians died in the allied bombings? How many German cities reduced to rubble? Germany divided with a huge chunk belonging to the ex Soviet Union, the ultimate open air prison? The allies destroyed many parts of Germany and many Germans to this day suffer from the division between communist east and democratic west. Sadly, peace, sometimes comes at a price. This is a fight against evil, Hamas is evil. Literally in the ultimate sense of the word: evil.
In any case, Gaza declared war on Israel. If Hamas cared about their own people, they'd return the hostages.