I don't know why you'd want to. TLoZ has never been about freedom of roleplay in the RPG sense. The option to murder NPCs for whatever reason in RPGs is there if players want to play their role that way. But Link is Link. The focus of TLoZ isn't on playing a roll and expressing yourself through your actions. This form of expression is unnecessary.
It would also stand in stark contrast to the series' tone, and it would impact the series' reception and rating.
That having been said, murder isn't out of the question as far as I'm concerned. Sakkon the thief from Majora's Mask is notable for being the only killable NPC in a Zelda game. Thing is, his death makes sense for the situation in which it could take place. It's actually not the optimal outcome from a strategic standpoint since it eliminates useful options that otherwise become available later. Plus, given that time resets throughout the game his death isn't final. It also initially happens only by accident if you didn't expect it to play out that way. Murdering NPCs in this way is entertaining and useful and even personally impactful to players, but I don't think players need the option to go around indiscriminately killing anyone they please.