If it was black who were incarcerated the most because of drug laws, it doesn’t make it racist.
Moreover, even if you know upfront that black people will be incarcerated the most because of drug laws, it doesn’t make that war racist.
(Moreover the quote in the linked article clearly states that hippies were also the target of the war on drugs, which, even if the quotes are correct and not taken out of context etc., make this war at least not fully racist.)
If we of course use the dictionary definition of the word racism, not extremely wide interpretation used today.
Some people were racists of course. But most people just thought harsher law on drugs would make communities safer. And most government actors just wanted more power regardless of who is going to get in jail.
It is much much more complicated issue than (quoting the comment I replied to) “Straight facts, it was all about the racism”.