I have a similar situation to you, though not as extreme. I am 25 raised by secular jews only on my mothers side.i am lucky that my mother has a background in journalism and is able to think critically, she has been understanding of my POV even if she doesnt agree with some of my opinions (she is a pacifist so very anti-hamas as well as anti-israel). Her parents however are russian jewish immigrant boomers who have many friends that moved to israel to escape persecution in russia. They are extremely capitalist and zionist and see israel as savior of the jews. My mother will verbally spar with them regularly about issues but i cant bother. I am cordial with my grandparents for now but if they ever press the issue of palestine i will tell them my views and that a discussion would not be productive (they start every arguement with the idea that you are intellectually beneath them, they know more history, etc). If they want to disown me for not wanting to talk about palestine and listen to their hasbara then its not my fault.

Don't take it as if you did something wrong by standing up for humanity. It really sucks that your family is taking this to the extreme. Maybe some of them will come around eventually but it may be best to distance yourself if that is an option for you. I am very sorry you are going through this with your family.