Some distros like Void seem to patch this out.[1]
From mandoc/mdocml's mandoc_char(7) [2]
In roff(7) documents, the minus sign is normally written as ‘\-’. In manual pages, some style guides recommend to also use ‘\-’ if an ASCII 0x2d “hyphen-minus” output glyph that can be copied and pasted is desired in output modes supporting it, for example in -T utf8 and -T html. But currently, no practically relevant manual page formatter requires that subtlety, so in manual pages, it is sufficient to write plain ‘-’ to represent hyphen, minus, and hyphen-minus.
Which is the common-sense thing to do.
Meanwhile, GNU projects become increasingly less relevant due to obnoxiousness like this.
In general the amount of wankery of "the correct hyphen" is staggering.
[1]: https://man.openbsd.org/mandoc_char
[2]: https://github.com/void-linux/void-packages/blob/20c66829134...