> so the documentation is trying to talk them out of...

What documentation though? There's an internal comment but it's not documentation and it's not really arguing against the use of this type of comparison (just against use of the implemented function).

If the documentation for this function went on along the lines of "we discourage the use of 3 way compares as we consider it an antipattern, do X instead, there's literally no reason to ever use 3 way compares, we know it, here's why..." maybe, but it doesn't.

Now, maybe 3 way comparison is not common but it is a distinct operation with known optimization opportunities. I wouldn't readily claim that the operation is not needed by anyone.