For all we know, the comment came from someone who was doing their job (by your definition) and were bitten in the behind by colleagues who did not do their job. We do not live in an ideal world. Some people are sloppy because they don't know, don't care, or simply don't have the time to do it properly. One cannot put their full faith into comments because of that.

(Please note: I'm not arguing against comments. I'm simply arguing that trusting comments is problematic. It is understandable why some people would prefer to have clearly written code over clearly commented code.)