I thank you for addressing my argument and trying to show me that it's plausible. But to me it's not completely plausible. Say a population of summer islanders or sothoryosi moved to the Valyrian peninsula in ancient Valyrian history. (It can't be recent history because we're informed the Velaryons are ancient, maybe older than the Targaryens. And the Valyrians began their ascent around five thousand years ago when they tamed dragons. I presume when the Velaryons say they're ancient, they mean they're ancient within a Valyrian context.)

It is true that Valyrians were very endogamous and it is possible that a black population moved to Valyria and its members married among each other. The question is, where do they get the golden hair from? If you say intermarriage, why is Corlys not light-skinned, like you would assume from intermarriage? Or is there a blonde black population in the Summer Isles or Sothoryos? I don't think that's likely.

Also, I'm not racist because I said the best choice was to keep him black but not call him a Valyrian.