"either nation can let in or out as much as they wish through the crossing they control, neither has control of the other's border crossing, and thus neither has total control."
The key issue here is "land, air and sea." Yes, of course, if we're simply comparing land access, then Israel isn't doing much that Egypt, or any other country, isn't doing regarding its border. It's the control over Gaza's airspace and territorial waters that most makes this situation unlike others. This is why Gaza is often referred to as an open air prison and Singapore, for example, isn't.
As for water, yes, you're right, "took control" doesn't capture the full nuance of the situation. I've gotten into the habit of talking about "control" of water because since Oct 7th, Israel has clearly set about using access to water as a weapon of war. Not only cutting off the supply they provided, but destroying desalination plants which has left Gazans almost entirely dependent on their water supply. 96% of the water from the coastal aquifer, according to the UN, is unfit for human consumption due to contamination.
This goes back to the overall question of whether Israel is at war with Hamas or the Palestinian people. When you knowingly attack water access to 2 million people, it's hard to make the case that you're only targeting Hamas.
This is further complicated by power, which, as you say, is required for the desalination plants as well as hospitals, heating, maintaining sanitation, and so on. The situation in Gaza has been dire for decades. I really don't think you can argue that Israel had any serious intention of improving conditions there before this latest chapter of the conflict.
Haha, yes, if there's one thing I've learned it's not to take activist talking points at face value. Though I do hold myself to less rigorous standards in conversations than I do when I'm writing articles. I'd spend all day researching my phrasing for countless conversations if I didn't (though I do appreciate the feedback, "take control" of water will find its way back out of my vocabulary). But to be clear, so, *so* many of the talking points I hear about Israel are simply activist talking points in the other direction. I don't think it's at all fair to present this as a liberal or mainstream (which is essentially liberal) problem.
Part of the problem with so many issues, and the reason there's sometimes blurring around the edges of things, is that there's often a big difference between an official policy or a political talking point and how it plays out in people's lives. *None* of this is as simple as the picture painted for us by the media or by activists.