As long as it’s opt-in (which it is), I’m not sure I understand the concern. You’d have to enable it.
Go has been routing module requests through GOPROXY since modules were introduced; it’s where all of the mod version is cached, so any time anyone builds a Go package from source, calls are made to the mother ship. Unless the builder is running their own proxy, which is mostly corps, who care less about this sort of telemetry. There are good, valid reasons for the main Go proxy, but it’s certainly also a valid concern that the Go core dev team is utterly deaf to.
In any case, the only thing that’s new is the telemetry which, as I mentioned, is opt-in. I don’t see any reason for new concern.