[bq]This is very philosophical question, why random generator in artist mind is something different from random generator inside the generator[/bq]
Because random generator in artist mind has multiple steps, and choosing the character to draw — is one of them.
[bq]Also, it is was AI generator developer intention, to take existing characters into training set.[/bq]
Right now it's a question of realization, you cannot be 100% sure, that this "Rainbow Dash" was generated solely by "Rainbow Dash" pics. And it causes huge amount of borderline cases:
- should this be tagged as Rainbow Dash? Canon character does not have a horn — https://thisponydoesnotexist.net/v1/w2x-redo/jpgs/seed91950.jpg
- should this be tagged as Pinkie Pie? Canon character does not have a white line in mane — https://thisponydoesnotexist.net/v1/w2x-redo/jpgs/seed62816.jpg
- should this be tagged as Rarity? There are dozens of OCs with more similar design — https://thisponydoesnotexist.net/v1/w2x-redo/jpgs/seed64832.jpg
Difference with your case is that you intentionally fed only Fluttershy pics. Result of uncontrollable mix of multiple character is really pain to moderate.
Oh, and wait until some artists will recognize their style and ask to tag them.