No, they did it because:

[being an overgrown social group] cannot diminish how awesome they are.

Also the public backlash, like you said.

Absolutely. But no, I don't think he's made it better in any way - and that wasn't the point. Ever since he was locked into the purchase the plan seems to have changed into running it into the ground.

There's no way they can maintain the $13bn debt he saddled it with, most of what he's been doing is something of a farce to cover up that as the reason for the business closing - eg "those advertisers leaving are going to kill the business!" That, and any of the dodgy shit they get away with (like API charges) becomes the norm for any future social media platforms.

Basic data analysis should have caught that a non goverment body was important enough to exempt, but they just didn’t do it.

What kind of "basic data analysis" are you referring to? I mean, it would be nice if that was a practical idea, to assess nearly every Twitter account and determine if it should have an exemption, but I don't see that it is. You either have an insanely labour-intensive process, or you have an imperfect automated process. Or, you just draw a line in the sand, as they did.

I don't think you can claim that Twitter has a "responsibility" in any meaningful sense, either. It's a private website, they get to set the rules and change them as they see fit. That's how it's always been. The responsibility lies with the organisations tasked with distributing the information (which also doesn't include NERV, they do it voluntarily).

I don't even think Musk made this change to try and make money - in my opinion, ever since he was locked into the purchase the plan changed to running it into the ground. On the way down, Musk can experiment with all sorts of horrible things - such as API charges - and while they won't get away with everything, the things they do get away with will set the standard for any social media platforms that come after the business ceases operations (primarily due to the debt accrued in the leveraged buyout Musk performed).

So yeah, Musk doesn't give any shits, the whole operation is intentionally destructive. But like I say, he didn't drop the ball here with Japan, he did it ages ago.