Did they say “Fuck Israelis”? You have to be either really thin-skinned to take offense to “Fuck insert country here”, or you support the thing that’s being criticized (which in this case is genocide).
Like, I’m Canadian, and when First Nations people say “Fuck Canada” because of the centuries of oppression and genocide they’ve faced, I don’t take personal offense because I do not support the genocide of First Nations people. They’re right, fuck Canada.