If you take the analogy of alcohol, legalization limits the proof of alcohol. When it was illegal people made alcohol that was really strong, like rubbing alcohol or dangerous due to impurities. A legal version of a control substance can be a safer version. And the access to the safer legal version could reduce demand for another version.
[O] “by snorting through nasal passages, the drug appears in the blood three to five minutes after use, with about 30 to 60 percent of the drug being absorbed into the bloodstream. Maximum physiological effects occur within 40 minutes, and maximum psychotropic effects occur within 20 minutes. Physiological and psychotropic effects fade in 45 to 60 minutes. By comparison, crack cocaine is not soluble in water and therefore can only be readily smoked. Smoking the drug produces a quicker onset, shorter duration, and more intense effects than snorting powder cocaine.61 Facilitated by the large surface area of the lungs’ air sacs, smoked crack cocaine is absorbed almost immediately into the bloodstream and reaches the brain in only 19 seconds, with 30 to 60 percent of the drug being absorbed into the bloodstream. Maximum physiological effects from smoking crack cocaine are attained within two minutes; maximum psychotropic effects occur within one minute. These effects are experienced for a shorter period of time than for snorted powder cocaine, i.e. between 10 and 20 minutes, but are similar to injected powder cocaine. In sum, although both powder cocaine and crack cocaine are potentially addictive, administering the drug in a manner that maximizes the effect (e.g., injecting or smoking) increases the risk of addiction. It is this difference in typical methods of administration, not differences in the inherent properties of the two forms of the drugs, that makes crack cocaine more potentially addictive to typical users. Smoking crack cocaine produces quicker onset of, shorter-lasting, and more intense effects than snorting powder cocaine. These factors in turn result in a greater likelihood that the user will administer the drug more frequently to sustain these shorter “highs” and develop an addiction.”
One of the more intractable aspects of "systemic racism" is that even without any animus, when the majority moves on from an issue, minorities get dragged along. Thus why it took decades for even moderate sentencing reform, despite a general consensus emerging much earlier. Everybody admitting to the same general problems isn't even half the battle; most of the battle is in prioritization, particularities, and process. (This dynamic is also the crux of Dave Chapelle's critique of the Woke movement wrt to how it prioritizes the demands of other minority communities over those of the black community.)