In terms of "colonialism" I don't think it quite fits the strict definition of the word. Again it's a bit of a unique situation. If we compare to Europe many of the borders were drawn as a result of war, and this would be no different. The difference is that in Europe the population might have been expelled (e.g. like: https://en.wikipedia.org/wiki/Expulsion_of_Germans_from_Czec... ) and the area annexed. Another interesting history to look at is: https://en.wikipedia.org/wiki/List_of_national_border_change...
That's not that obvious considering all the illegal settlements. I'm sure they want the land just not the people living there.
But yes, no clear solution especially considering that the only (non-Hamas) option for self government, the Palestinian Authority/Fatah is thoroughly incompetent and corrupt.
EDIT: Just want to add that the reality is more nuanced. Naturally Israel affects control over its border with Gaza and Egypt affected control over its border. Israel has definitely refused to let Gaza operate an airport or a sea port and so it maintained some amount of control together with Egypt. That said a lot of how this evolved was around choices made by Palestinians and the rise of Hamas led to the official blockade being imposed. I do think this was an opportunity for Palestinians to demonstrate how they can govern territory controlled by them and be peaceful neighbors which ofcourse did not happen.
Nobody in the former Ottoman Empire did.
> No sovereign country would tolerate a complete blockade of its borders
Plenty of enclave countries exist. The blockade clamped shut when Hamas took power [1]. A coup, mind you, which overthrew Gaza’s fledgling (and flawed) democracy.
[1] https://en.m.wikipedia.org/wiki/Blockade_of_the_Gaza_Strip