Well, you've successfully constructed a hell of a strawman! My comment was to express my support for the following statement:
> I'd say more generally, it's about control and having something police / government can hold over almost anyone, or any demographic, if convenient for whatever reason.
I didn't say anything about Democrats or Republicans. I happened to use a quote that touched on Nixon in support of my claim.
I would also note, for people not well-versed in American history, that up until around the 1960s, the concept of a Southern Democrat still existed - people mostly identified with opposing desegregation in the American south. Some of these politicians, including Strom Thurmond, who voted against civil rights and for the Controlled Substances Act, later became Republican figureheads. Party ideals shift over time.
With that said, I don't think the current state of drug laws in the US are an issue of party. It's a lack of evidence-based policy, and it's extremely problematic.
One might not blame politicians for looking at the effects of narcotics and their relation to organized crime in the mid-20th century in America and say: "we need to legislate this, because the problem is ballooning and we don't have any other tools at our disposal." Addiction science didn't exist yet.
One might even forgive the Controlled Substances Act as an extension of this reaction, were it not for the fact that through the subsequent creation of the DEA and the scheduling system, the effects of drugs and addiction became significantly more difficult to research in the US. This happened under Nixon, and I think that's why he receives a significant portion of the blame for the current state of affairs (rightly or wrongly).
The DEA has also simply failed in its remit. They've shown themselves to be completely incapable of assessing the medical utility and controlling the abuse potential of drugs (marijuana on the one hand, prescription opioids on the other). This, combined with the fact that the CSA and the DEA's existence prevent us as a country from evaluating other approaches to the drug problem, make for a lose-lose situation.