If this were true, how did the drug laws passed in the 70's hang around for so long? If there was no reason but racism, why didn't Obama, who in his first term had super majorities in Congress, simply wipe them away? You take away the agency and voices of people who live in crime ridden poor neighborhoods which suffer the consequences of high levels of addiction.
In the capital of my state, in just the last few weeks, we've had people high on pcp attack cops (after strangling his girlfriend), shoot at traffic, and pick up a child out of a stroller and slam them on the ground, all unprovoked. Those victims aren't racist in wanting to not have to deal with people high out of their minds.
You're essentially asking why Obama, a fairly centrist liberal by many accounts, didn't end racism forever.
There's a very good reason why black people are disproportionately arrested for drug-related crimes, especially Marijuana, despite having similar usage rates as others.
There's also the fact that members of the Nixon administration outright admitted this fact.
The reason Obama didn't do anything isn't that he's not that worked up over racism, it's just not as simple as waving your hand and saying everything would be great if it only for those racist laws. Drugs reduce inhibitions. People with reduced inhibitions do crazy things, often hurting other people. Families are often willing to support draconian measures so that their kids aren't endangered by some random stranger in some drug induced state of manic paranoia.
In the capital of my state, in just the last few weeks, we've had people high on pcp attack cops (after strangling his girlfriend), shoot at traffic, and pick up a child out of a stroller and slam them on the ground, all unprovoked. Those victims aren't racist in wanting to not have to deal with people high out of their minds.