Dear Aditya,
A good workforce of any establishment or factory is a asset and there is no harm if the HR indulge into settlement of any sort of complaint / dispute whether within or outside the premises.
Moreover, I do not feel any harm if the HR even get involve into personal issues of the workforce. I remember, when I was in service, I had settled certain minor disputes within the family of workers or their friend circle, understand their problems whether relating to the school admission of their wards or medical treatment of their parents etc. etc. by advancing money either from my employer or from my own pocket. At the same time taking appropriate disciplinary action against the guilty is equally important to maintain discipline and peaceful working. In this particular case, if the employee has used abusive language through email it is on the record and HR can go through it, understand the circumstances and situations and decide further action.
It is a goodwill gesture and you can win over the hearts of the workforce. They will definitely listen to your directions always.
P K Sharma