On what basis are you asserting this as being fact? It clearly isn’t more than an unsubstantiated opinion
I'm not asserting is fact at all, but I am paraphrasing what some have said about how insulting it is to not see MM as mixed-race because she is relatively light-skinned.
It is simply not plausible or credible to suggest that DB, with his specific history, was unaware of the racist connotations of the example he was drawing.
No-one denies, not DB himself, that after the facts, he was aware that a) MM is mixed-race, and that b) there is a racist trope of black people = monkeys/apes.
The subtle distinction is whether he was thinking that at the time he made the post.
Expressions and imagery related to apes and monkeys are pretty commonplace. The expressions "pay peanuts, get monkeys", talking of your child as "little monkey", or aping around come to mind. So is the concept of a circus animal.
Secondly, I do think not everyone labels people by their race immediately. I'm taking my experience of someone whose partner is mixed race. I'm not, and wasn't conscious of it when we met. If you asked me, and I was filling in the census form, I would write mixed race, but it's not at the forefront of my mind. I don't go through work, consciously thinking of my black colleagues as black. I'm not claiming not to see race, I'm just saying it's not at the forefront of my mind that Dave from Accounts is Black.
What suggests to me that Danny Baker didn't have racist intentions in mind is that when the connotations were pointed out to him, he deleted the post. He then went off to apologise (not very well at first). Lastly, this is someone who has no history of racism in his 40 years in the media.