I get what you are saying in general Northerbear, but in this case I don't think the original poster necessarily confessed to any major misdeed when he started this thread.
He rearended someone, and as a long time claims adjuster I can tell you that while I have no statistics to back it up, my impression is that the majority of accidents that come across my desk are rearender's one way or the other (either hitting or being hit).
Was he careless? Yes (an accident did happen), and he'll probably like anyone who's been in an accident wonder about how much worse it could have been, and be thankful no one was hurt. At the end of the day though, even the best of drivers don't give one hundred percent of the attention that they should while driving all of the time, so really it could happen to anyone and that's why we have insurance.
As for the careless charge I wouldn't read too much into that; See my original thoughts on the accident, but basically in brief "Careless" is getting to be a more common charge as it serves as an easier to prove "blanket charge" that's intended to be plead down to a lesser charge.