Turn on "showdead" in your profile, then look at their comments. Usually it's easy to tell why it's happened, but if there are comments that don't deserve to b

Turn on "showdead" in your profile, then look at their comments. Usually it's easy to tell why it's happened, but if there are comments that don't deserve to be dead, you can "vouch" for them individually to help resurrect them (click on comment timestamp, then click "vouch"). That has happened here.