Some humans don't have souls. APD might be one of them. Most of your serial killers and rapist don't have souls.
Are you saying that you lose your soul by being scum, or people are scum as a result of not having souls? On topic; I don't see why not. Silicone instead of flesh would be a ludicriously arbitary reason to not have a soul, if they do indeed exist.
I don't think Cortana has a soul, because you can't kill her. She's not a living thing, she's a really complex computer program based off of a living thing's brain. To which you can break her or you can delete her but you can't kill her, technically.
But then again, if you can digitize humans into data with the composer, then who the **** even knows at this point.