fuzz, toughen-up man. You are the one whos car was stolen. You have every right to be angry that your car was stolen and
NOONE can legally or other wise do anything to you for getting whatever help you can to recover your car or be compensated for it. If they were negligent and there is not more to this story than you are telling us !! You should be the one pushing for court not him. This only speeds the process up for you !!.
You will only be in trouble if you openly slander the Car Washes name and cost him business. Be careful with that, and that alone.
Like I told you before.You should get legal advise and you should be suing him NOT the other way around. This is just a scare-tactic. (that appears to be working).
No one can stop you being a member here or anywhere else for that matter It is in Fact Unlawful-You just have to be careful not to mention names in public forums.
Good luck either way !!