I don't like it when people post songs that have hateful lyrics/ expressing hate/anger/disgust about someone else.
It clearly has no good intentions and I think it is more hurtful than backstabbing.
The receiver person who is involved and fully aware of the evil person's situation is put into a very tragic spot. S/he cannot assume or deny. Add to that agony that person's love for music if s/he is well engaged with music and the words played.
Well I would easily get hurt or be affected when I see a friend do that to me. I just don't get it why you're doing this. Better sign off from you.