And considering in the interview they’ve said it wasn’t a senior royal who questioned his skin colour, I would suggest there’s zero evidence that’s why.
It doesn't have to be a senior Royal to influence the decision. I always assumed the implication when they said it wasn't a relative or senior royal was that it was one of the senior advisers to the Queen, either one of her private secretaries or someone on the privy council - ie the people who spend their lives telling her what she can and can't do or what's best for her.
These were the same people who told the Queen and Charles they shound't try and stop the media circus around Diana, said they shouldn't sue the papers to stop the harrassment and I think they make up the establishment Harry has hated since he was a kid because they stopped his close family acting like family to each other.