It isn't always support of "apartheid" governance or an issue with the Islamic faith.
For some it is the fact that Hamas was wrong, and continues to be wrong, in their actions.
Israel is doing the palestinian people a favor by eradicating their oppressors that haven't let them vote for 16+ years, have used billions in donated money intended for infrastructure to make rudimentary rockets and dig a tunnel system for the purpose of engaging in terrorism instead.
It's like college students moaning they can't afford their $200 electric bill on their $1500 iPhone with $125/mo service plan, while sipping a $7 coffee everyday at Starbucks.
Skip Starbucks and you got your electric bill money with ten dollars left over 😉.
Skip the rockets and terrorist tunnels and they would have their own water and sewer system.
It ain't the Israelis' fault Hamas, which is the elected government of the palestinians, misappropriated funds.
If Hamas cared about their fellow muslims, brothers of the Islamic faith, they would do whatever was necessary to end their suffering.
Return hostages and lay down arms.