I’d compare it to e.g. the work on async/await in Rust, where the discussion seems more directly “we like this feature that C# pioneered and JS has adopted, here’s how we plan to adapt it to make it work well with Rust.”

Admittedly, the Rust async/await RFC and the Go contracts proposal both discuss prior art in sections towards the end, so they are actually similar in that respect. Maybe it’s really just a question of tone and messaging, and the particular discussions that tend to end up on HN.