Everything in RP games is dependent on the relative maturity of everyone involved and what sort of game they enjoy.
How old are the Paladin player and his friends? 12 years old? Are they just playing as murder-hobos in a video game? If so, then nobody cares.
Are the Paladin and his friends (allegedly) adults? Do they have an interest in Role Playing? If so, they should be able to discuss things like morality and how disturbing it would be to actually kill a sentient being who was begging for mercy. (The DM should carefully describe the scene. The panic and then the agony as the goblin painfully dies of blood loss and how its last words were something that translates as "At least I'll be with you soon, Mother.").
How old are the Paladin player and his friends? 12 years old? Are they just playing as murder-hobos in a video game? If so, then nobody cares.
Are the Paladin and his friends (allegedly) adults? Do they have an interest in Role Playing? If so, they should be able to discuss things like morality and how disturbing it would be to actually kill a sentient being who was begging for mercy. (The DM should carefully describe the scene. The panic and then the agony as the goblin painfully dies of blood loss and how its last words were something that translates as "At least I'll be with you soon, Mother.").