Isn't the entire point behind using URIs as "modules URIs" that it's decentralized so the load is spread across hosts and there isn't a single point of failure? Is Golang proxying all those fetches regardless?
It is: https://proxy.golang.org/. The goal is faster module downloads, and to an extent prevent users from hitting GitHub/etc ratelimits
A temporary solution to the issue is to remove proxying for packages download: