It's very odd that 'baby talk' is professional. I don't think society was always this way. I also respect anyone who questions why this is the case. Assuming it's an efficiency, we should be able to justify this behavior.
The non software people climbed the hierarchy not because they are competent at their jobs, in fact a highly competent person will often be passed over for promotion because they are useful where they are - but because of how they negotiated very complex social networks.
A senior manager, my manager at the time felt that with very little skill to separate the people working at the company, ascendancy was about positioning yourself in bullying networks, and he described this this kind of 'baby talk' as a subservience signal in which you were surrendering to and accepting a manager as your patron and any further advancement you made was by their grace.
If you chose to do the 'honest talk' with someone senior to you, it came with a risk and a potential reward, you had to do it well enough to convince them you were a worthy formidable peer and an ally. If you did it unconvincingly you would be struck down.
This seemed to be a widely held worldview and therefore more or less the social reality in the non software parts of the business. I was free to do 'honest talk' because as a software person, I was clearly to the side of the game, it wasn't really possible for me to fall or climb too far.