I think it a matter of preference lol, its sexually aesthetic like that (for me) its like those unnecessary thread when the top penis inside bot hole or unnecessary skin colored drolling saliva or oddly some add in skin colored fangs, it really just preference...
It looks more like a mistake to me, because I (maybe) remember the main character having pubic hair the same color as his actual hair. And I would say the same thing if I saw flesh colored teeth or saliva. I'm not sure about the other thing you said, because I don't know what it is you mean. And if it's intentional that's even worse, because it's lazy.
Why the fuck is their pubic hair flesh colored?? I prefer they just blur it out if they're going to forget to color it in. How does no one notice that??