But here's an answer based on UX analysis: I don't have a definitive answer for why Apple made the decision they did. So, what is the benefit to using a black cursor with a white outline, rather than a white one with black? Certainly when I think of the Windows cursor, I think of it being more precise for some reason. Thus, there must be a benefit to this, but one does not come to mind. than any other OS), so they likely didn't pick the design of their cursor for such an arbitrary reason as 'it's different'.
However, since I've used Mac OS more, I've realized that it's very heavily geared towards visual arts (a much more advanced color picker, font book, display profiler, etc. I used to think that this is because the designers of Mac OS wanted it to be different from Windows, so they used an inverted palette for the cursor, and then designers of other operating systems used the same as Mac OS because of the same reason, or because Mac OS is 'cooler'. I've used a lot of operating systems, and those that support mouse cursors usually default to a black one with a white outline, with the notable exception of Windows.