West Bank is more complicated, but the same concept applies.
If Israel was motivated by racist or other tendencies to want to impose apartheid, they would start with the areas they have full control over. Why would they allow Arab voting if they are trying to impose apartheid?
"OK don't worry about oval ones. Just consider the round ones."
All this aside, I don't think you understand what is meant by Apartheid. This is coming from a South African who grew up during that era.
Gaza does not have borders it controls, Israel controls Gaza's air and sea borders.