Because to them they are discussing the topic of the disapparence. And they have the right to do that as much as any other topic.
There's a thread on here by someone claiming to be an MP's wife.
She is very upset by press coverage of the expenses row and threads on MN about this.
Should we all not discuss this because one person finds it upsetting?
Just about anything is upsetting to someone.
You have brought up the other board over and over and how it upsets you. You stick the boot in all the time and speculate about why certain posters are missing.
Should you not be allowed to do so anymore because others find that upsetting and feel they have done nothing wrong?
No, of course not.
Same goes for all topic bar those which are obscene or racist or the like.