My ancestors were Irish too, on both sides. There were no Palestinians before 1917. They were part of the Turkish Ottoman Empite for 400 years, but were liberated by the British and given the name Palestine after the Roman Province of Palestina. They have a much less valid claim of Israelis who have continuously occupied the land for 3000 years.
The Palestinians have stronger genetic lineage to the original inhabitants than the Eastern Europeans calling themselves Jews. There were conversions and an influx of Muslims over the centuries, but the original peasant farmers never left.