There is nothing wrong with the location, unless you mean that restaurant specifically. Los Angeles is a HUGE city and like all huge cities has a lot to offer, both good and bad. I've been to some of your smaller cities and they lack the good part but still seem to have the bad part.
Valley Village, the area where this occurred, is a perfectly safe part of L.A. It is a nice, pleasant neighborhood where an act of violence such as this is probably a "once in 100 years" type of thing. The street where the restaurant is located is a commercial busy street. Like a lot of areas in American cities, the closer to the busy commercial street you are, the cheaper and schitier the residential RE is. Valley Village is not Beverly Hills or Pasadena by any means but it's far from a slum. Decent part of the valley.
I knew that it was Armenians, I said Russian as a short-hand. That's not a mistake you want to make in their presence.
"People from the former Soviet Union" would have been more precise. I know a lot of Armenians, mostly in Los Angeles but some back in Minnesota as well. They are well-represented in the highest levels of achievement in American life, as well as the world. In the blue-collar world, a lot of people in the automotive repair industry are Armenian in L.A. I count several as friends and the only generalisation to be made about them is that they are some of the best people I've ever met. They are really sharply divided as a group between good, honest people and crooks but the good ones are as honest as the day is long. They are known for their word being absolutely iron-clad.
Here are a couple more articles about the shooting and the place where it happened:
4 men killed at Valley Village restaurant were targeted, LAPD says | L.A. NOW | Los Angeles Times
This one has quotes from neighbors about the strangeness of that establishment before the shooting:
Police Believe Victims Were Targeted in Deadly Valley Restaurant Shooting - LAist