Well, one aspect is that, as the article mentions is that Israel has declared itself a “Jewish State”. That’s a problem when a majority of your population (when you include the West Bank and Gaza) or a sizeable minority (excluding those two regions) are explicitly not Jewish / Palestinian. Just imagine if apartheid South Africa claimed they were a “white ethnostate”?

Also, maybe more to your point, Palestinians in the West Bank and Gaza are not allowed to vote in Israeli elections despite not having meaningful autonomy (ostensibly the reason Israel disenfranchises them). This conveniently makes Palestinians the voting minority in Israel where otherwise they would be the majority without this one weird trick. If that’s not apartheid I don’t know what is.