If Tesla offered to buy the car back from the people who sign this letter but you had to sign something saying you would never buy a Tesla again and wouldn't talk with the media, would that be acceptable? You would get a full refund and would get out of this situation with a company you don't trust and could move on to a car that you would enjoy better.
That's pretty much an all or nothing scenario. I haven't heard any "I hate Tesla, I'm done!" from anyone here. Most folks seem to love their cars and the company (in general), but simply want what they paid for. They shouldn't be banished for that.