I have a very poor memory for faces and names, to the extent that I have taught identical twins in separate classes for multiple years without noticing the fact they were twins. I do not recall my own teacher's names, nor many of the names of people I have been friends with at workplaces over the years. I think there is something in my brain that does not store this information correctly. I have to work very hard with things like revising the seating plan to get around my unbelievably poor name/face recognition and I can assure you there is no laziness or lack of care involved. Over the summer holidays, I forget a great many names and have to start almost from scratch in September. If I close my eyes, I struggle to picture my own children, though I can strangely recall specific pictures of them quite clearly.
At school, I mix up blonde girls, red heads, boys with the same haircut. I mix up teachers names as well. We don't have many black children in my school, but we had two black girls who were the same age, build and had very similar haircuts. I use a random boy girl seating plan with new classes and it unfortunately placed both of these girls in the same seat, at different times of the day. Unfortunately, I use seating plans to remember names almost exclusively, at least at first. I absolutely got their names mixed up. I felt horrendous, it was far worse because of the implication that I was racist for doing this. The students totally noticed and looked at me with disgust when I did it, otherwise I would probably not have noticed my error immediately.
I have ensured that I sit children from ethnic minorities in completely different areas of the classroom now (I live in a very white area). I have always spent additional time in learning BAME children's names to ensure that I do not make the mistakes I make with white children with them, because of the far worse optics. Perhaps this is a form of racism in itself, but it is my practical solution.
On a tangentially related note, the amount of effort it takes for me to differentiate the Louis's between the Loo-ees and the Lewises is simply insane.