MDMA is an interesting one because its far along in the official legalization path as a prescription drug but it doesn't fall into the decriminalization statues typically because it is synthetic (most of them make an exception for naturally derived psychedelics -- so even something very powerful like DMT is covered).
In practice, however, MDMA is widely available via the same channels as other psychedelics which are typically not the same distribution channels for much more habit forming and harm causing drugs like heroin, fentanyl, or cocaine.
Drugs are a complex and nuanced topic, I think it's perfectly reasonable to be pro drugs and also wary of how Instagram is vetting their drug advertisers.
Black market goods vary in quality and ethics and safety, it's absolutely reasonable to say, "ok, you advertise for these, how are you ensuring safety?"
Succinctly, it's okay to want to change the law, and also favor rule of law.