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".
In the same way "colored people" can gain these connotations, just from other few people (falsely or not) inferring that it has those connotations. There need not be a history. I've seen too many blowups over the years about the word niggardly to think otherwise (more than one of these has made national news in the last few decades).
It's not that there is a history of discrimination, it's that we've all made a public sport out of demonstrating how not-racist we are, and people are constantly trying to invent new strategies to qualify for the world championships.
> It's not that there is a history of discrimination
In abstract theory, that would be possible.
In concrete reality, with "colored people", there is, in fact, a history of discrimination, and when the context of use is not such that there is a clear separation from that history (a separation that exists in, e.g., the NAACP continuing to use "colored people" in its name) it has become problematic because of that history.
Such is claimed. Which are the false accusations, which are the legitimate accusations, and which are merely the mistaken accusations? And how are each of those quantified? If someone actually tells me the numbers, how do I know that those are the correct numbers? And why should I believe them? Is there a reason to believe those, other than trying to qualify for the world championship "I am not a racist" games? If my skepticism is also racism, I then lack the means to be and remain rational about the subject, and if I can't be rational about it then I am with 100% certainty being manipulated with regards to the subject.
Are you allowed to be skeptical? Do you feel as if you're allowed to be skeptical? If you do feel as if you are allowed to be skeptical, why are you not?