So is your issue here that a CEO makes public claims if his company that may be predictions or aspirations for the future, then sells shares he owns in the company to buy another company?

Exactly my issue. The same way scams are "predictions and future aspirations".

Fair enough. I may just be cynical enough to assume CEOs are always talking out of their ass with regards to the future, but I do understand if people would rather things not work this way.

That was to buy Twitter.

Does using the money from the dump to do something else make it no longer a dump?

I'm fairly sure this was not a pump-and-dump.

My evidence is that in America people sue for these things left and right all the time. It's a popular pastime for lawyers to get a class action lawsuit for securities fraud together. But as far as I can tell, Musk / Tesla weren't convicted of these things in conjunction with the sale of Tesla stock to buy Twitter.

There is a meme for this kind of move. It's pump and dump because it isn't worth what the underlying assets are worth and because there is a sale. Whether people sue for it and whether or not they were convicted is immaterial.