The FBI UCR table 43 '
Arrests by Race and Ethnicity relies on actual arrests; 2018' shows that of Drug Abuse Violations arrests (1,234,178), Whites were 50% (minus Hisp/Latinos racially included as White), Blacks were 27%, and Hisp/Lat were 20%. That's a far cry from the graph you presented.
Table 43
'Usage' is determined solely via survey by SAMHSA to the question of "have you used XXX in the past month, and past year". It reveals nothing about frequency or length of usage. It also say nothing about where, how and whom you use and/or buy from, and there are differences between blacks and whites. There are studies indicating minority groups, none more than blacks, under-report and even deny usage, even when it is accompanied by hair and urine analysis and do the same re: criminally delinquent activity generally.
To default to 'racism' ignores the obvious; that poor urban neighborhoods have higher crime and that urban poverty centers have high black populations. By necessity, these areas are rightfully given more police attention and the majority of black people do not want fewer police there, but more or at least the same number. They understand what learned outsiders who pretend to speak for them do not, because they LIVE there. It's not "just gang-bangers killing each other" but good, black Americans live there, too. And they deserve better than to be invisible under the yoke of predominantly Democrat, Great Society governance making election cycle promises that never had their welfare in consideration, but their political fealty.