Yeah, exactly. It depends what's being written about. I don't think a white person can write authoritatively about certain aspects of racism just as I can't write authoritatively on certain aspects of being a woman.

There's plenty of overlap in the human experience, but some parts are kind of siloed off.

That said, I have no doubt that white people can speak very well on certain aspects of racism. There's plenty of data around, which is more valuable than personal experience in many cases. There are also plenty of things that can be seen, regardless of the colour of your skin, simply by paying attention.

White people are obviously less motivated (or forced) to pay that attention than black people, so they're more likely to have blind spots. But then some black people are so drained or bitter about racism that they have blind spots of their own.

TLDR; yes, I think white people can write credibly about certain aspects of racism. Probably less credibly about others.