I don’t want to seem like a pedant, but I think it’s important in this case.

Why?

Why is it so important that racial prejudice and racism not be considered the same thing?

Why is it that we can't just say "systemic racism" when we're referring to systemic racism – instead we've got to reserve the word "racism" exclusively for systemic instances, and use the comparatively softer and less stinging "racial prejudice" for everything else?

Could it be because the people pushing this know that "racism" is a harsh term, and have a vested interest in making sure it can't be applied to them?

Could it be that they don't actually think racial prejudice is wrong on principle, only wrong in who tends to get targeted, and they want to excuse their own racial prejudices?

Could it be that they're trying to exploit the gap in perception of what "racism" means, and by declaring "Only white people can be racist" they know that most people will interpret that as "Only white people can be racially prejudiced", thereby reinforcing the idea that their own racial prejudices somehow don't count?

It's a motte-and-bailey fallacy. The bailey: "Racial prejudice by non-white people is excusable." The motte: "Hey now, we're just playing around with the dictionary."