To understand much of our language, Gnorts would have to already be aware that our words and symbols gain meaning from how they're used, and you couldn't, for instance, determine that a swastika is offensive (in the west) by its shape alone.
In this case, the term "colored people" gained racist connotations from its history of being used for discrimination and segregation - and avoiding it for that reason is the primary principle at play. There's also the secondary/less universal principle of preferring "person-first language".
Tattoos can change, too. If I had a tattoo like that, but had come to see the error of my ways, I would have it removed, or if that was too costly and time-consuming (it takes a year or so of painful, expensive, periodic laser treatments to remove a tattoo), I'd have a tattoo artist cover it up with something else.
There's no excuse for keeping a neo-Nazi tattoo if you stop being a neo-Nazi and realize that neo-Nazis are disgusting people.