Whilst I've no doubt that the preference for blonde in the modern world intersects with race, scientific studies have shown that the preferences for blonde are largely evolutionary.
Because blondes tend to have lighter skin imperfections can be seen more easily, thus illness and infectious diseases can be detected more easily by a partner.
Blondes are a mutation and therefore 'rare' so would stand out more than their brunette peers.
Aging can be seen more on blondes, so men could more accurately assess who was of fertile age than on brunettes.
Paternity is more easily detected in recessive genes of blue, red and blonde hair so this was a factor. (One of the main reasons queen Elizabeth the 1st was able to escape accusations of bastardy)
All these reasons predate mass interracial migration so the preference for blonde being hardwired cannot be put down to simply racism.
Obviously, nowadays racism will play a part because in the modern world it's something we run into more regularly, but it is not the most dominant factor.
And I think people offering up they have children with blonde hair and blue eyes is because your premise is that dark hair and eyes make misgendering more likely.
And, as shown on this thread, people don't feel as comfortable complimenting afros in case they are accused of microaggessions, as someone did upthread. For the record, my white baby has curly hair and it's literally commented on all the time. Probably because without it he'd look like every other baby and toddler: a potato.
But it's a bit sad to read that if I compliment a black child in the same way, it is read as racism. It's literally a conversation starter. I.e. in my case.
Stranger: oh what lovely hair
Me: he gets it from his dad. I have to pay for my perms.
Stranger. Haha, we always want what we don't have....
If you read commenting on hair as a microagression people have less to compliment. So they might not strike up conversation. This is harder the younger they are, sure toddlers might interact and we can comment on that, but only positively, so you have to wait for positive behaviour. And the end result is people avoid talking to you in case they offend you. Which means you are more isolated. Which is then interpreted as racism.
It makes it a bit of a minefield tbh.