I mean couldn't he have killed Maeglin,which would remove any stain on soul of my namesake's cousin.Or Uldor for that matter-two damn traitors!
But nooo.He had to kill Lalaith,Nienor and Gorlim.It's true that Gorlim is a traitor too,and that Nienor committed sin,but lo and behold! Gorlim and Nienor both did it for LOVE! And Morgoth just had to kill those three innocent souls instead of two REAL traitors,which are Maeglin and Uldor! I mean,only psycho could do such a thing!