The war on drugs has destroyed many lives of people in majorities as well, from poor all the way up to wealthy. This doesn't have to be a divisive issue. It's a human issue.
Statistically the poor and minorities get treated worse with harsher sentences for the same offense. Don't you think it's strange that it was all about being "tough on crime" when drugs were happening in the inner city but it's all about "treating drug abuse as a disease" when it's illegal use of prescription drugs in the burbs? Drug dealers in the inner city get locked up. Doctors who over prescribe because they get "marketing assistance" may get a slap on the wrist if that.
No, I don't think it is strange. It has little if anything to do with "poor and minorities" or "inner city". It is about purpose for use and the credentials of the supplier.
People trust doctors. People expect that this will not be a problem. People have sympathy for those who are addicted due to having, perhaps wrongly, trusted a doctor. That doctor is a paid professional, highly trained, and expected to provide for your health.
Consider a similar situation. A person gets a house built, moves into it, and it collapses. They might have hired a licensed general contractor, or they might have paid a random person they found sitting outside the hardware store. The difference matters. Similarly, one could hire a licensed pilot or somebody who took just a couple lessons. You may die either way, but one way gets much more sympathy.
There is also the matter of need. The doctor is supposedly supplying drugs for a purpose beyond "it would be fun". There is no respect for people who gamble with their health just to have fun. Somebody who just got a hip replacement is understood to need painkillers. Visible needs are obviously legitimate. If there is no visible problem, the assumption is that the usage is just for fun.
BTW, for these purposes, the start of the addiction is what counts. The current drug supplier matters much less than the initial drug supplier.
The war on pot/crack was Nixon's way of attacking democrats since people in prison can't vote, that's less votes for democrats in elections. He targeted specifically drugs used by those demographics, I believe that's why people were more likely to get off using white-collar drugs than crack or pot.