I truly believe that an individual can get an unpopular rating by his colleagues very easily if he simply does not fit into their little world of right and wrong.
Every one goes through difficult times in their lives - during these times ones behaviour might be seen as controversial.
A system of unofficial references must never be used (and for very good reason is illegal) as pilots are so quick to act as judge, jury and prison warder when someone has not acted the way that they would like. And the mud often sticks many years down the line when that person may have worked very hard to get the himself back on top and is now totally competent. This site is proof of those facts.
If there are flaws in the training and selection processes within our industry then these must be addressed. Only when an official system proves an individual unable to carry out their duties safely can action be taken.
I suggest chief pilots spend their time addressing these points rather than digging into personal closets.
I think this is the point being made by Holtcj.