Sued? Twitter said that there were only "x%" of bots, and multiple independent bodies found that Twitter mis-represented material facts in the number of bots. This is what we call "fraud". In fact, what will likely happen next is that advertisers, who were promised an engagement platform of reaching potential customers, were in fact, paying inflated prices to advertise to non-entity bots. That is fraud, against multiple advertisers, over years. Share Holders, who were told in SEC filings that Twitter engaged with some number of people on their platform, were lied to.
Yet, somehow all of Twitter's fraud is Musk's fault? If I were to sell you a car, and you found out I lied about the mileage on the car, the year of the car, the accident record of the car, the maintenance issues with the car, and even something as basic as the size of the engine in the car - because of fraud, any contract is NULL and VOID. It's not rocket science.