Is the idea that if you're no longer a shareholder, this makes you bad?
As opposed to long term traders, who are not trying to make a profit?
Ideally, in a lawsuit, you want the plaintiff to have suffered some kind of harm at the hands of the defendant.
Yes, you can tactically become a shareholder and file suits as some people do all the time. You miss earning you get hit by a shareholder lawsuit every time. This is not a rare thing, but also does not necessarily imply they have any reasonable claim to any damages. Could be just leeching.
The distinction between this and the SEC matter that was settled is that SEC is supposed to care about the integrity of the market at large, not just Tesla, Inc. shareholders doing well at the cost of other players in the market that were misled. That's a much stronger basis to argue for damages.
Tesla's stock went down below 200 in May of 2019, well after the tweet and skyrocketed after that. The long term performance of Tesla stock is not the result of that tweet in August of 2018 and that tweet was not representative of creation of long term value. If Musk hadn't tweeted that day, I would bet long-term performance for Tesla shareholders would have been identical.
If Musk actually had funding secured and did take the company private, recent share prices might even indicate that would have been against the long term interests of Tesla shareholders as they were betting on the long-term results of Tesla's investments in manufacturing and would have been deprived of the gains from that bet that they are seeing now.
Holding a short position is similar to having a friend with a spare old car. Their lazy kid is going to get a job and their license eventually, and they definitely want to have the car for that, but who knows when that will be. You buy it for $3,000, promising they can have the car back whenever they want. But you sell it immediately to a third party. You're planning to buy them a replacement car on the used market when the car depreciates (they'll never know the difference), hopefully next year that old gas guzzler engine is even less popular and that model year's styling is considered even more dated. When your friend asks for the car back, you'll buy one for $2,000 and make a tidy profit! What happened to these folks was that the car didn't depreciate from $3,000 to $2,000 like they expected it to, that model had the lead role in a blockbuster movie and overnight, it became a coveted classic car. Turns out there are only a couple hundred still on the road, and now, if your friend asks for it back, you'll have to go to a big auction and pay $50,000 to replace it, suffering a loss 4700% greater than the profit you expected to make.
This is a lawsuit for car owNers, not car owe-ers. The owners are $47,000 richer, they don't want to sue the car manufacturer, regardless of any underhanded dealings that got it that movie role.
Again, I agree that your post above might serve as an avenue to claim some damages that a judge would agree to, but to say stock price today is immaterial is just plain wrong. If the stock price had dropped to $100 today, it would have been likely that all shareholders could make a valid argument to a claim, but now at the very least one has to demonstrate that they were a shareholder at the time of the tweet, and they have taken a certain action that hurt them based on that tweet.
Why does this matter?