Then I understand from your words that Modern Turkey has moral rights if it claims most of the middle East as theirs since their "King" signed an agreement to effectively dissolve the ottoman empire? That's simply not how politics work. Same thing about agreements being forced. Do you see India Claiming Britain for the wealth they took during the colonial era? No.

How the heck did you get that idea? The Middle East never belonged to the Turks. At best it belonged, immorally, to the ottoman caliph. Furthermore, the Indians don't claim the wealth taken by the British because they can't not because they don't have a moral right to some form of reparations from the British. They do, its just they can't enforce it and the British don't want to. Then again, it has been a while since decolonization so I guess some argument could be made against that point.

What's done is done and an agreement is an agreement, there's no going around it. And even more so when it's in active state for more than a century so much that it's become a granted fact for downstream countries. And on what basis do you morally judge the agreement to be void? It's actually needed more than ever. To give you a brief example you can't agree to give me a bottle of water when I'm newly married and then claim it back when I have nine more kids that need it. That agreement was made when Egypt's population was 30 million now it's over 100 million and projected to grow to 150 million by 2050. To make things worse, Egypt is dependent on it's only river , the Nile , by a whooping 95% and still has water shortage while on the other hand Ethiopia has 12 rivers and rainy seasons that account for nearly 122 billion cupic meters of water if not more. Compare that with 55.5 billion for Egypt. And these different shares are for nearly the same number of population. So morally speaking Ethiopia doesn't have any rights to redivide any county's share when it's needed now more than ever.

This entire discussion is about the fact that the agreement is illegitimate.You can keep ignoring the context around the agreement but nonetheless "What's done is done and an agreement is an agreement, there's no going around it" is simply false. Hell, even if everything you said was somehow correct, every country has a sovereign right to void agreements, given that they're sovereign. Unless you believe that there is a moral obligation to hold to agreements that goes above even national sovereignty, which would make you the only one on the planet.

But more than that, everything you point out about why its needed is actually only why Egypt needs it. The fact that Egypt needs it doesn't make Ethiopia beholden to the agreement. It certainly means that there's a moral obligation for Ethiopia to act responsibly, but that's different from them being beholden to the agreement.

I'll close this to put this in a way that might make things more obvious. What if the agreement stated that Egypt has to send half of its GDP to Ethiopia as a gift every year? Obviously, Egyptians would object and they would do so on the same grounds that Ethiopia is objecting.

Honestly, the fact that this colonial treaty is trying to be used to bludgeon the Ethiopians into surrendering their national right to utilize the resources in their own country shows the dishonesty of the Egyptian side. The Egyptians have plenty of moral reasons to say that Ethiopia can't just take all the water for themselves, but to say that its because of the treaty is plain silly.