The British and French and Europe generally denied the entire world self-determination in that time period: literally every state surrounding Israel is the product of Sykes-Picot, just as one instance. Horrible ethnic violence and subjugation has been in endemic in all of those states. Israeli Jewish people, who are themselves plurality MENA people (contrary to the popular narrative that they're all displaced Europeans), correctly notice that they're the only ones whose residency is invalidated by appeals to the British.
None of this is to say that Israel's treatment of Gaza is defensible; rather, just to point out that you don't have to pick at the history of the region to make your case, especially because doing so isn't going to help you make that case.
I don't know of any other case in modern times in which the British or French promised a country to people who didn't even live there.
British colonial administrators themselves quickly came to realize the insanity of what they were doing. The Balfour Declaration was basically a declaration of war against the population they were ruling over in Palestine, a population whose interests they were nominally supposed to rule in. Lord Curzon, who was the only British cabinet minister with expertise in the Middle East, warned about this before the Balfour Declaration was issued.
> Israeli Jewish people, who are themselves plurality MENA people (contrary to the popular narrative that they're all displaced Europeans)
Israel was founded pretty much solely by European Jews. Arab Jews emigrated to Israel years after it was founded, because the expulsion of the Palestinians and the Arab-Israeli conflict unleashed a wave of antisemitism across the Arab world.
None of this is to say that Israel's treatment of Gaza is defensible; rather, just to point out that you don't have to pick at the history of the region to make your case, especially because doing so isn't going to help you make that case.