I don't think it's fair to describe the Go proxy as "calls home"; no one says that about Rubygems, PyPI, npm, or any other package tool. If anything, the Go proxy is the only package system that actually allows disabling it quite easily and pain-free. Try using Ruby without rubygems or React without npm: no doubt possible, but it will take a lot more effort.
The Go equivalent of `gem`, `pip`, `npm`, `apt`, `cargo`, etc, is `go get`. There's no issue with `go get` connecting to internet.
On the other hand, `go build`, `ruby`, `python`, `node`, `gcc`, `rustc`, have no business doing anything that requires the network (obviously `node` etc are interpreters, so the user's program could have networking code, but that's the user's code, and not the interpreter's code).
So, `go get` using Google's proxy by default, fine, this is Google's tooling, we can just avoid using `go get`.
But the problem is that this proxy sneakily creeps into the `go build` command as well, so you can't just "not use `go get`" because you have to set flags for the compiler as well.
IP addresses being the only "personal" data the new telemetry proposal would plausibly be able to gather as well, which a lot of folks are complaining about.
Just to be clear, I don't think the Go module proxy is a bad thing, just saying that we've already crossed that "threshold" of potential personal data collection long ago.
That said, I don’t think that the go tool’s current behavior in regards to the module proxy server can be considered as phoning home.
The proposed metrics collection however absolutely would be bad phoning home behavior.
So does Rubygems, PyPI, npm, or any other package tool.
If you want to have a broader discussion about package tools: be my guest. But people misrepresenting and banging on about the Go proxy specifically got boring a long time ago.
What I am arguing is that the people who are saying "this new telemetry design could allow them to gather ip addresses - which are 'personal' data" are arguing over a ship that has sailed years ago.
Apologies if I wasn't being clear enough.