>Feels like it's encouraging vigilantism and 'taking the law into your own hands', which is not something a well run society should be incentivising.
No, citizens acting on their own and society's behalf should always be incentivized versus infantilizing everyone into helplessness and dependence. A home intruder being summarily despatched by an armed homeowner, for example, is a far superior outcome than the homeowner suffering whatever the intruder subjects him to while hoping the "authorities" intervene on his behalf. Not to mention the improbability of any true justice being delivered via the legal system.