A good episode with my own real problem being Mariner vaporizing holographic versions of her crew mates with no real remorse. Yes, they are holograms, but these are people she works and lives with. Earlier this year, she was attractive to Ransom, now she's killing him. I understand she's blowing off steam and I've seen comments that this is akin to "playing a video game," but it's like playing a first person shooter video game in your workplace.
If it were feasible to play a customizable first-person shooter with realistic versions of real people the way it is to make a holoprogram, I'm sure it would be the most popular game out there. And I'm also sure that the overwhelming majority of people would be able to distinguish between the fantasy of shooting co-workers, friends, family, etc. and acting on those fantasy impulses in the real world.
The tiny fraction who might not would probably have the same difficulty distinguishing between shooting aliens in Halo or cops in the Grand Theft Auto series versus real people.
You may be familiar with the Voyager episode "Worst Case Scenario." It's one where Tuvok had secretly started a holodeck training situation that involved the Maquis engaging in a rebellion but never finished it. Paris and Torres stumble on it, and it becomes a popular thing among the crew, to the point that everyone wonders who created it. When Tuvok reveals it was he and that he stopped because he felt it might be harmful, Janeway tells him to loosen up. He and Paris work to complete it (which would have been fine but for that meddling Seska). Now his program, "Insurrection Alpha," is obviously less shooty than Crisis Point, but it even more than it has the potential to stir up resentments.
I just don't see any meaningful difference between shooting a simulated version of someone you know, versus shooting a simulated person and fantasizing it is someone you know, versus shooting a simulated person who is being controlled by someone you know.
To me, the only problematic part of the whole affair is that Boimler had taken seven years of people's personal logs to create the base simulation and make it more realistic. As Rutherford touches on, those are supposed to be private and invading someone's privacy is not cool. But I don't harsh on Geordi for doing something similar in creating holo-Leah Brahms in Booby Trap (though he used only publicly available sources, it's still kinda creepy). So I'm willing to give Boimler a pass.