Somebody who messed up but acknowledges it as a mistake, and is therefore unlikely to repeat it, may be more valuable as an employee than a random new hire who may or may not make the same mistake again in the future.
Of course, someone who makes a 'mistake' that is in fact indicative of an underlying personality flaw or tendency towards bad judgement, is a liability and best gotten rid of. The job of a manager is to decide when a person is one versus the other.
http://blogs.atlassian.com/2014/06/failing-values-team-indus...
> I know the engineer responsible well. I hired him. I know the slide does not reflect his values any more than it reflects Atlassian’s, and he is as deeply sorry as we are. It was an error in judgment, but one the company shares responsibility for making.
> As Atlassian, we don’t stand behind the slide – but we stand as a team. When we do good, and when we do bad. Today, we failed as a team. We will help him learn from this, as we all must. Our engineer, our event, our issue, our learning, our growing – as a team.
It specifically mentioned "[his] girlfriend". Although potentially cringe-worthy, there was no generalization. The contents could have been entirely factual.