Thanks for the explanation, I can totally empathize with someone making a link between a phrase that means something negative and a term which they identify themselves with.
I'm curious about the whole host of other abstract terms which could connote a similar negative meaning if we associated their terms with racial meaning, though. I listed some above, but I'll elaborate here:
* White bread (boring), or white noise (something not worth listening to)
* Brown-noser (a suck-up)
* Yellow journalism (sensationalist news, doubling up on an offensive term for Asian people if we choose to racialize the term)
If the little kid in the example above picked up on racial biases against any of the previous racial groups, and associated that racial group with one of the phrases above, I would expect that they'd be similarly upset.
It seems reasonable, then, to explain to anyone concerned that these are not racialized terms, rather than trying to prevent offense from terms that bear no relation to the perceived slight. I have no objection to the terms "denylist" or "excludelist", but "blacklist" also seems perfectly fine when used in a technical context.
In much the same way, the terms above could all be replaced as well:
* White bread -> Plain bread
* White noise -> Full-spectrum noise
* Brown-noser -> Suck-up
* Yellow journalism -> Sensationalist journalism
* Black comedy -> Taboo-related comedy
If one wanted to use any of the terms on the right, I'd be more than happy to read them (just as I'm happy to read "blocklist" or "excludelist"). It does not follow, though, that I should stop using the terms on the left -- the fact that someone might be offended if they assume that the phrase is racially motivated (especially if it conforms to other racial prejudices they've experienced) is definitely terrible for that person. The solution, though, is to make it clear that such phrases are not racially motivated, rather than to assume that such terms are implicitly racialized.
tl;dr: There are lots of phrases, across different groups that could be offensive if they were assumed to be related to that group's identity, but which aren't actually related. We could choose to remove these phrases from our vocabulary, or we could clarify when terms refer to extremely long-standing color associations vs. when they refer to racial concepts that use the same language. I have no qualms with people that choose to do the former, but I see no reason to be any less okay with people that choose to do the latter.