Inevitably, Jews and Jewish life would be one of the targets. Keyboard cretins who would not dare to say something in person, and who would be barred from getting their thoughts into the printed media, will feel embolden to express antisemitic views on Twitter.
I suspect Israel would also suffer a bombardment of falsehoods from those who have the time, or the funding, to attack it as the source of the world's woes. Naturally, they would also conveniently ignore the real villains (and who may in fact be the ones financing them).
I do hope I am wrong, and one way to avoid this fate would be for Musk to ensure Twitter has strict guidelines as to fact-checking of information. It will also need to be clear about the source of tweets, so that they are not the product of bots and state propaganda.
In addition, just as newspapers can suffer financial penalties if certain rules are breached, Twitter needs hard-edged regulation so as to protect both its own integrity and the reputational safety of others.
If Musk is going to be in charge of what he calls the “town square”, he needs to take care it does not turn into the town urinal.