The issue which I understand is primary with fentanyl is purchasing black market fentanyl and selling it on the street as heroin or whatever other opiate and cutting it with various things leading to a wild variety of potency of street drugs, even within the same purchase (poorly ground, poorly mixed) which leads drug users to overdose much more frequently.

Fentanyl, absolutely is safer than many other popular pharmaceutical opiates but only when the dosing is done competently and accurately (even someone abusing opiates is safer using fentanyl IFF they are capable of knowing and distributing their desired dose)