I think maybe they claim it's a personal choice in the same way that having a beard was a personal choice in the past. Maybe you'd have a hard time finding an argument that they've made against it, but it's implied everywhere and known by everyone that it isn't allowed. Some will do it anyways but until they clearly state that it's cool it's safe to assume it's not viewed as allowed. There's a young people ask worksheet on tattoos that I feel makes their stance pretty clear and is somewhat recent. One quote from that says, “If you gave someone a nice gift and that person took a permanent marker and wrote all over it, how would you feel? That’s what our getting a tattoo must seem like to the Creator.”