Thanks to @npr for giving national press to this issue.
Click here for their full article.

Good news: Tattooers are standing up to show that melanin does not “take away half your skill sets,” proving that if something can’t be done then it’s an issue of a lazy or ignorant artist, not the client’s heritage.

See recent examples on dark skin: 
tattrx.com/tagged/melanin

Bad news: For the (many) tattooers who still lighten the images of darker skin, or delete them altogether, saying your work just “looks best on lighter skin,” I can’t change you but @tattrx definitely won’t be supporting you.