Imagine if I moved into you house and moved you and your family to the bathroom and then 40 years later I offered to let you use part of the backyard would you accept that and be happy?
70 years ago they had the whole area and then through British weakness a bunch of displaced Europeans moved in against their will and pretty much evicted them why do you think they wont accept 10% of the land they once owned with a smile?
Seriously this isn't rocket science you have two people who cant and wont live together peaceably laying claim to the same piece of dirt and until you can find a fix that BOTH parties (not just one) can live with you will always have the problem.
We are more often treacherous through weakness than through calculation. ~Francois De La Rochefoucauld