DRAC2GUNZ

Given the constructs of the world within DayZ it's completely realistic. Ammo and Guns are incredibly easy to come by and there's almost no "Should I save this bullet to save my life later or use it to kill this person who is in no position to harm me just because I can?" going through your head. There's no repercussions for murdering people either, IRL some (certainly not all) people would be ridden with guilt after killing someone they had no idea was innocent or not, there's no way to simulate this in a game in a realistic fashion. Basically everyone who plays this game with friends utilizes a 3rd party VOIP system so they can communicate both secretly (only the people in their Skype call/Vent/TS/etc. can hear what they're saying) and across the entire map, and due to this fact, shooting on sight is just a safer way to do things because if you let them know what you have/where you are, there's a good chance they'll tell their buddies. There's also practically no punishment for dying besides like 30s before you respawn depending on your PC/connection/the server. Maybe dying needs a bigger wait time, like mandatory 30min on that server (so you can't go loot your body/get revenge so easily) before you can respawn. Also, comparing people shooting on sight in DayZ (an alleged "realistic" take on a zombie apocalypse with countless unrealistic features) to literal psychotic killers IRL, is just ridiculous.