For me it’s less about trustworthiness and more about what they can do with the information. Google can potentially locate, profile and influence everyone around me and I don’t want that type of power however benevolent they are.
What can OpenAI do? They can sell my data, whatever, it’s a whole bunch of prompts of me asking for function and API syntax.
Do you think Google doesn't sell that data, or that other companies don't collect and resell it?
In either case, I'm sure that's how it starts. "This company has very little power and influence; what damage can they do?"
Until, oh so suddenly, they're tracking and profiling you and selling that data.