It's always okay to kill a virtual copy of any person on the basis that they're not real as they can simply be duplicated and manipulated in the same way as any other data or software on a machine - a machine which I own. Because I own the machine which houses them, if I can create them, copy them, etc, I can decide to kill them at my will.
> How do you know you're not running in a simulation right now, etc etc.
Ultimately, I don't care. If I'm running on someone's console and they can hit ctrl+c on me, then they can do that, there's nothing morally wrong with them doing that because they own me at a much deeper level, I run on their hardware.
In the same way that I'm okay with abortion, I'm okay with this - your dependence on someone or something else is a defining factor of your rights as an individual. If you depend on a machine that someone else is free to control, their rights trump yours.