Yes, everybody makes mistakes. But whether we should be tolerant depends on the nature of the mistake. If the driver had been distracted because they made the mistake of deciding to use their cellphone while driving, should we react by saying "don't worry about it, I'm fallible too"? What about the cardiac surgeon who is "thinking about something else" while she has your child's heart in her hands? "Oh well, you should see some of the things I've screwed up"?

Errors are made in all fields of activity. But telling people they don't matter, that it's OK not to pay attention, is not good policy.