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".
they’re not colored, they’re African-American
they’re not African-American, they’re black
they’re not black, they’re Black
they’re not Black, they’re People of Color
they’re not People of Color, they’re BIPOC
I wonder what the next twist of the pretzel will look like