Thanks to Cromar Scott for the link.
Great anecdotes there.
I especially liked his comments about companies "You cannot trust code that you didn't totally create yourself. (Especially code from companies that employ people like me)."
Exactly the thought that gives me that particular part of the reason - basis for postulation. It's called "history".
Intent of malice by a company employee for any of the major software and hardware distributors is a possibility at all times just as any other security issue is. I won't ignore it or not talk about it because of a possibility of liable, stupidity, ignorance or trolls.
Neither should anyone else.
What is the big deal with this particular sticking point?
The justification for the question is glaring.
Any fundamental security doctrine requires us to take into account the possibility.
TF.