The conservative black was nice but the cardigan is, I think, a bit too informal, especially in light of the queen’s outfit. A nice suit would have been better. The cardigan has a “Mr. Roger’s formality” about it.
Expecially if you are the Present of the USA's wife.
Even if it is the real Queen of England---Elton John---and you are a man or a woman.
She’s trash. She has no clue when it comes to social graces, protocol, etc. An embarrassment to us in the US.