I think the problem is there is enough stale documentation and valid-but-not-recent documentation that you regularly encounter both which makes distinguishing the two cases difficult
I find the op's perspective weird as well, though I have colleagues which reason like this at well when I point to those blogs/talks of 2014-2016 during reviews -- "that can't be the way to do it 8 years later right?"
You are missing the point, documentation is either evergreen, or it is not. If you don't clearly state whether your documentation is current, then it leads to a lot of confusion.
I'd like to other blogs which of announcement of being current. There are deprecated notice I have seen, else things are considered current by default.
