How dare you.
Bonnie, I have been active on message boards for some years. It is important you understand when you ask a question on a message board, a free message board, you are going to get whatever response the participants feel like giving. In this case, their responses violate no message board rules. It was not necessary to tell us you had cosigned for the car; that was your decision.
Car talk message board covers many aspects of car ownership. That includes buying a car the person can afford, appropriate to their circumstances. You can, of course, do what you want. But, when you come on a message board which routinely discusses such economic issues, then it is reasonable to expect the topic to come up, but especially so if you introduced it, and you did indeed.
In this case, while it is too late to undo it, the person did buy a car inappropriate to his/her circumstances, or you would not have had to cosign.
That issue is part of our regular discussion here. We dare because that is what we do here. All issues of car ownership are discussed here. Sorry you didn’t know that, and got into something that you are not happy with.