My comments about it, I hope, makes it clear just why it becomes so *grating* when white people with tattoos, piercings, who are punk, or whatever the fuck else white people do to show their counter-culture individuality, equate their whatever experiences they have for their increased visibility with the experiences of dark skinned PoC, or visibly genderescent and/or trans people, or anyone who lacks any real choice about how visible they are and the ways that this visibility negatively impacts their lives (also inclusive of disabled people, fat people, women, etc. and all intersections thereof).
White people, your choice to become visible is predicated on the notion that you are the default human, thus you must do something extra achieve the same level of visibility that various marginalized bodies experience.
It is not only the assholeishness of engaging in a false equivalence (choice to get tattooed = skin colour) but it reenforces the white supremacist notion that you are default and, thus, normal.
all of this.
This was a huge problem with the original description for a panel I was on at WisCon about body acceptance—which not coincidentally, only attracted White panelists in its first incarnation. We did get it significantly changed, although for other reasons it ended up still being fairly disastrous (ask cypheroftyr). But the original panel totally seemed to equate tattoos and piercings and shit with being a POC, which is fucked up and would certainly explain why no POC had volunteered to be on the panel as it was written.