Because openAI is the least trustworthy of the Big LLM providers. See S(c)am Altman's track record, especially his early comments in senate hearings where:

* he warned of engagement-optimisation strategies, like social media, being used for chatbots / LLMs.

* also, he warned that "ads would be the last resort" for LLM companies.

Both of his own warnings he casually ignored as ChatGPT / openAI has now fully converted to Facebook's tactics of "move fast and break things" - even if it is society itself. A complete turn away from the original AI for science lab it was founded as, which explains why every real (founding) ML scientist has left the company years ago.

While still being for-profit outfits, at least DeepMind and Anthrophic are headed by actual scientists not marketing guys.