A lot of people were born in Israel, and so did not have a choice about being on occupied land. It is also within someones means to change their mind on the matter. I'm not saying there are many people like that, in fact the percentage is quite small since the Israeli governments approval ratings are consistently high.
One of them was on Al Jazeera or BBC News during the Gaza war/massacre. I think his name was "Yonatan Shapira", he was in the Israeli army before he realised his actions were wrong. Since then I've heard of more.
True, it just seems like in order for an "Israeli" to be against the occupation of Palestine they would have to be against Israel in totality including calling themselves Israelis, since the whole country was built on the occupation, and if that occupation had not taken place they would not exist.
salam