> - The main public opinion driver for both the needle exchange programs and the decriminalization was a _massive_ Heroin epidemic

There were politicians that publicly spoke about their personal experiences. Others that had family members that were caught up with it.

It was a widespread issue across all classes, not just the poor.

Here's a recent interview about one of the main drivers of this policy (in Portuguese).

https://www.perguntarnaoofende.pt/pno/joao-goulao