It shows that the intent continues to be racist. This disparity is ongoing, not historical; if it's truly not racist, why not bring the amount of possession charges in line with usage?
It shows the impact, not the intent, continues to be racist. It doesn't really say anything about intent, at least without a lot more data. If white and black usage differ in kind somehow - say, pot brownies vs smoking on the street (I have no idea if there is a racial disparity here) - it could lead to a difference in police involvement without any racial discrimination.
If I go fishing for redfish I’m going to end up catching a lot more saltwater fish incidentally. Doesn’t mean I hate freshwater fish, that just means in not fishing in an area where I’m going to find many freshwater fish.