That's a bit of a sideshow. Tesla needs to worry about the civil liability involved in making a car that stops suddenly in the middle of the road. For example, "The driver is still 100% responsible, just as they would be for cruise control" is absolutely not going to impress anyone as a defense if there is enough property damage or personal injury involving such a feature to justify a class action.
Class action vs. direct action is immaterial; Tesla can't disclaim it's liability for manufacturing g defects even if it tried, and stating that the driver remains responsible for following traffic laws isn't even superficially a disclaimer of product defect liability anyway.
Product defect liability is strict liability for damages produced, and there's a fairly high bar for excluding liability due to intervening causes which would not generally apply to the simple negligence of a driver (either of a Tesla or the other involved vehicle) which contributed to a collision where the defective operation of an assist system was also a contributing cause.
Anyone can sue anyone in the US. Take it up with their general counsel.
“Any person driving a vehicle on a highway shall drive the same at a careful and prudent speed not greater than nor less than is reasonable and proper, having due regard to the traffic, surface and width of the highway and any other conditions then existing, and no person shall drive any vehicle upon a highway at a speed greater than will permit the driver to bring it to a stop within the assured clear distance ahead.”
Maybe if you have a dash cam. Maybe if you can prove there was nothing in front of the person in front of you. Lot of maybes.