It's obvious that Golang is Google's language. The most obvious part is they require a CLA that gives them and only them special rights. It's a sham.
Even the linux kernel has a CLA, they just call it by another name (Developer Certificate of Origin)
Node had a CLA, but it was removed in 2014. It does have a "Certificate of Origin", which you claim is the same as a CLA, but I beg to differ. The issue here is that CLAs generally require you to reassign copyright; the Certificate of Origin does not. That's the part of CLAs that the OP is taking issue with.
Who is the single beneficiary of special rights granted under the DCO? CLAs provide a single party with rights nobody else has.
Basically signing over rights of what you contribute to the company running the project.