I know. It doesn't work well enough. If Google focussed on this I think gRPC would gain massive ground. But issues are left open for months without any response, etc.
We've had to drop gRPC as a direct result of this.
The person you're replying to clearly is willing to put in effort, but requires a minimum of guidance from the maintainers of the project. That's perfectly reasonable, and your passive-aggressive response is not justified.