I was supporting a variation in my head of the "Yeah but who wants to contribute to an SDK for a service that you need to pay for?" claim.
You can self-host for free, so maybe @hahn-kev don't mind contributing to the SDK now.
For me, I refuse to contribute to an open-source SDK for a non-foss product. And I refuse to self-host a non-foss product.
Personally, I don't care if non-foss licenses speeds development. So yeah in my case it's ideological.