The demand isn't being made to the product side; Discord and other chat clients already have a chat API which their clients authenticate and talk to, it's all already built and user-facing. They already distrust their clients. They already made everything a third party client would need.
It's a policy change, not a product change, and demanding a company adjust their bad policy is totally normal.
It's a policy change, not a product change, and demanding a company adjust their bad policy is totally normal.