A study (if it's a real study) can't tell you what should be done, it should give you new knowledge about the state of affairs. (while I agree that drug offense should be decriminalized).
Ehhh, most studies in this realm have a 'results' section and 'discussion' section. I disagree that experts in their field can't have an opinion laid out in the discussion section, given that it follows from the analysis and results from the previous sections. That being said, the page is currently timing out, so I can' even read the article...
The paper [1] really seems more like a call to action from ethicists published in a scientific journal as a study for whatever reason.
[1] https://www.tandfonline.com/doi/full/10.1080/15265161.2020.1...