Almost right.
The scene you refer to was a phone convo between Elena and Jen. Elena says she saw a porn comic where the creator had created an alternate universe where characters actually had pubic hair. Jen replies how weird that is because in their universe nobody had pubic hair.
If that had been the explanation initially, fine. Dev's choice, especially if this choice is made clear early.
But that's not what happened. It was alibi central with : shaving ; waxing ; why does anyone care?
If this "joke", as you call it, had been done from the outset, well and good. OK, then. All characters are 18+ and have no pubic hair. Players could decide for themselves how to interpret this info.
btw, another joke you may like is it was only after 0.11 did the dev-team finally get around to informing fans that DMD was set in an alternate universe.
IMHO, from a Dev perspective, it's just easier to keep things non-hairy: props, placement, texture, color, rendering, etc. Earlier pubic + body hair products weren't always foolproof or convincing, I felt. So, those may have been some practical factors in this case.
Plus, if one character has pubic hair, then would that mean the rest should, lest some of them stand out oddly? Well, except for Elena, perhaps. Essentially, that forces a normalization of hair and if the Devs were already shy of adding such, then they'd possibly punt altogether on the idea.
I noticed that ICSTOR offered a mix in Milfy City, but even that was minimal (and, they are a rather talented Daz3D artist).
I can post some comparisons in the art thread with my amateur version of D, if curious.
Of course, some people just like the shaved look - which is still quite common in "professional" adult porn, it seems.