Because a machine will never have a soul.
You don't need one. You only need an advanced / complex enough neural network
Only organic life can have a soul, spirit, etc., as I understand it. AI is just a computer program and it can only mimic human intelligence. It can get better at mimicking this over time, but that's all. It's a bit like a psychopath, honestly.
Does that mean that in your belief a psychopath has no "soul"?
Psychopaths are human beings.They can only mimic normal humans in order to fit in, but will never be one.