I'm not sure what you mean by "red". But as I've said, people did move around. And really, "all Celts were white" is arguably far less likely than "some Celts were not white".
The point of depicting a "typical" scenario is that you don't represent the 1% dark. In the same way that a representation of a "typical" household doesn't include a homeless man, a billionaire, and someone in between. The billionaire and the homeless man are not included because they are not representative of what is typical.
Sure, I get that. But it's been the rule to never show blacks in contexts where we know they existed, and were even common. So a little balance doesn't seem unreasonable.
Lying is still lying, even if you feel that the lie accomplishes some political agenda that you happen to believe in. In this case, if you say that this is a typical family when it is not, then the fact that you lied for what you think is a nobler purpose doesn't make this OK.
