Which vendor would you rather use in this context, with your sensitive customer data?
-vendor A's list of sub-processors is a mile long and includes providers of questionable repute;
-vendor B's list is short and includes AWS and GCP
I think he's arguing about OpenAI vendoring specifically, where OpenAI has a lot of subprocessors, but AWS doesn't and there's not really a 3rd camp to choose from, yet. But even there you can't just choose AWS as I tried to illustrate in uncle comment.
The politics of multimillion dollar contracts for public clouds go far, far, far beyond the preferences of an acquisition team, or what the engineers may think.