As I understand it, that's essentially OpenAI's defense here.
A more similar context would be: they ask Tom Hanks to create a voice similar to Woody, the cowboy from Toy Story . Tom Hanks says no, Disney says no. Then they ask you to voice their cowboy voice. It's obviously related: they tried the OG, failed, they're going for a copycat after.
But if never approached Tom Hanks or Disney, then there would be room for deniability - without mentions to real names, it would require someone to judge if it's an unauthorized copycat or just a random actor voicing a random cowboy voice.
It was a bad play from their part.
So in your opinion, if a movie needs to have a tall, skinny red head, and then they approach someone who has those qualities and the role is turned down, then it would be illegal to get any other different tall skinny red head.
That sounds absurd to me. If you have a role, obviously the role has qualities and requirements.
And just because person 1 who happens to have those qualities turns you down, it is still valid to get a different person who fulfils your original requirements.