They are talking about a particular group though, not the entire population like you seem to have taken it. When people say “fuck America”, they’re talking about the American powers that be (the government, corporations, military, etc. depending on context).

In this context, “fuck Israel” clearly is talking about the military powers. In religious contexts, some denominations of Abrahamic religions might say “fuck Israel” because of the land’s involvement in the story, and that wouldn’t mean the citizens either. It’d mean the religious institutions or the territory itself.