I'm not sure I would of used "unpopular", because work is not about popularity, but I think the point is that if you've got an employee who is causing problems or acting in a way that is damaging to the organization, then you, as an employer, have to deal with it. Whether "dealing with it" comes in the form of speaking with the person and explaining your expectations or terminating their employment, ignoring the situation is not (or shouldn't be) an option. Unfortunately, too often, that's what happens with the effect that people leave, productivity declines, absenteeism escalates and an environment is created where this disruptive behaviour is seen as acceptable.
I suppose, ultimately, it's a business decision, but one that can have profound implications on the organization to say nothing of the potential legal issues that can come out of it.
I've written about this previously (see for a sampling Workplace Bullying is Widespread, Toxic Leaders - Why do People Put Up With Them?, Dealing with the Narcissistic Boss, and The Implications of Not Dealing with the "Jerk").