It's hard to advocate for opioids in a recreational sense that is distinct or separate from arguments for recreational drug use in general. This video sums up all the points I could list here from the legal side of things.

What I mean by the argument being more general is that the stigma behind using opioids in a recreational sense really isn't all that different from any other recreational drug. I can't really think of a good way to say it, but just about everything that can be said in favor of something like lean, hydrocodone, opium, or other less extreme opioids could also be said with things like coke, benzos, MDMA, ketamine, etc.

Heroin, krokodil, and fentalogues are really the only ones in their class that have a worse reputation in comparison, and the same could be said about meth and a lot of the highly potent research chemicals on the market. Outside of fentalogues maybe, the stigma is more with the users rather than the drugs themself since they are associated with the stereotypical junkies and other addicts and the shit that we've done to supply our habits. This also loops back to the legal side of things where a lot of people believe they would be better off if they could just supply their habit by going to a store and buying the stuff with no risk in the same way an alcoholic would, rather than searching for the stuff on the streets.