TEL AVIV — Israel’s ferocious bombardment of the Gaza Strip will create an incubator for a new generation of terrorists, some extremism experts say, as thousands of young people who have lost families and homes risk being radicalized by the war and its likely chaotic aftermath. Israel says it wants to destroy Hamas, the terrorist group that carried out the massacre of more than 1,400 people and the kidnappings of 240 others on Oct. 7, according to official estimates. But Israel’s retaliatory bombing campaign has killed thousands of civilians, many of them women and children; reduced swaths of the tiny,...