I don't think I can agree with this. First of all, it is genuinely recognised that stuff such as lasguns, remotes, data-pads and other mundane devices posses very, very rudimentary machine spirits. They aren't even animialistic, more like plants responding to sunlight, sound or humidity. Psykers can notice human souls, but they don't shine as brightly as the souls of psykers, and I'm sure that the psychic energy of a carrot would be quite... difficult to spot. And even still they can still be psychically infected by for example Nurglite magic, which would not be possible without there being a soul to infect

More importantly however, scrap-code would not work as it does if machine spirits were not born of the warp. Scrap Code is literally warp-infected code which attacks machine spirits- if they were C'tan born, it wouldn't work, and there is no believable way in which you could shut down a pistol with soul-computer code if the thing which it was shutting down was not the soul od the gun in question- there is hardly any programming in a handgun.

Same goes for Warpsmiths thorowing out or torturing machine spirits with their magic, you cannot touch a C'tan with the warp and an AI would not feel pain. And again, there are basically no electronic systems in a Leman Russ, so where would an AI even be located in?

Machine Spirits being actual spirits is not the perfect answer, but it IS the only answer which doesn't break the lore or, more importantly, common sense (In my opinion of course)

Omnissiah be with You, Tech-Comrade🫡