Ok, FYI but “fetch” was relegated in the movie to irrelevance, ie, “stop trying to make fetch a thing.” So for the “fetch”-aware audience, the title reads, “Raft Is *Irrelevant*: … Explained Through Mean Girls”
Rachel McAdams finally snapped at her that the word was not going to catch on and that she should just stop. Tears were then shed.
No, they're claiming that "fetch" is interchangeable with "irrelevant" according to the movie.
This is clearly not stating that the actions by both parties are "irrelevant", it's clearly slang for "cool" or "awesome". The movie was alluding to the word itself being irrelevant in its use, not the word meaning or being synonymous with "irrelevant". I hope this cleared things up for you.
And if your "fetch" is the normalization of Mean Girls as a valid lede for didactic technical discourse, then you go Glen Coco.