Because if you don't discuss it then it leaves the collective consciousness.
Which plays into the hands of the perverts.
People always talk about what they would do if they met someone like this. The simple truth is that, for most people they would turn the other way. They chose not to have to cope with it.
Fortunately there are others who are willing to try to do something about it.
Unfortunately they are more ofter vilified than applauded.
Fortunately they don't do it for the praise, rather because it needs done. On behalf of the voiceless.