Damn I thought I'd get much negative responses. You guys are spot on with what I think. And the fact that the stone removes people at random from existence without any cold blooded murder, you can't really complain here.
The only problem is who gets to decide that, and that I guess is up to someone with a strong will. In the movie it seemed like the Universe really is asking Thanos to do the work for it, otherwise it could've just not given him the soul stone.
Going off a previous flashback, it just looked like people were picked off at random and they called it a day. He most likely literally left the killing to pure random chance with only the the goal of half the population. I mean he didn't even kill the people who actually stood a chance against him, so it wasn't something he decided upon.
Side note the scene where he got the soul stone legit made me cry. That was so emotional and powerful, showing not only how far he was willing to go, but a more human side to him. Showing that he could love someone and showing the actual struggles he was going through to do what he was doing.
Semi-random, as I said he has a honor code, he let it be random but he made it sure to fulfill his promise to Dr. Strange and let Tony Stark survive (sure will be fundamental in the next movie, as Strange specifically selected a "future" where he survives as the only option where they end up winning).
It's funny because he kind of acted like he wasn't in the right doing it, but more so feeling like was something he was required to do. He seemed greatly driven for the greater good at any cost and it wasn't about being right as was about bring balance.
To him balance wasn't about right or wrong, but meeting in the middle where neither side really win or loses. Basically he didn't decide to be right because there was no right answer.