That's interesting research, but I think a more important reason that you don't have access to them (not even via the bare Anthropic api) is to prevent distillation of the model by competitors (using the output of Anthropic's model to help train a new model).
If you can't trust a company, don't use their api or cloud services. No amount of external output will ever validate anything, ever. You never know what's really happening, just because you see some text they sent you.
Do you not see that the next (or previous) logical step would be a "commercial ban" of frontier models, all "distilled" from an enormous amount of copyrighted material?