If you're learning linguistics from wikipedia maybe check out "prescriptivism" and see how many contemporary mainstream linguists work within that framework for native speaker usages.
How does prescriptivism interact with wikipedia? Since wikipedia can (in the ideal at least) be edited by anyone, I'd expect it to match common usage more closely than a normal encyclopedia.
It is useless because it is nitpicking. But still, descriptive rules for a language can still be pretty specific and complicated, so even if we toss out all prescriptivism that won't free us from corrections I think.
It will because no "correction" is necessary. If the speaker's intent was understood by their audience then their usage was correct. If it was not understood, the audience will seek clarification and the intended meaning will emerge that way.
This sort of unsolicited "correction" of other people's language is unnecessary and basically never helpful outside of an explicit educational/language-learning context. The goal isn't to perfectly communicate according to a specific set of rules, and trying to ossify the descriptive "rules" in that way is just prescriptivism but slower. The goal is to understand and be understood, which will always be a context-dependent moving target.