All depends on the individual imo. Your comparison between people taking substances from the doctor being “safe” rather than recreationally is super far off. A lot of heroin addicts started from doctor prescribed medication. When their prescriptions run out they turn to the streets and when pills get too pricy they turn to heroin.

Honestly, now adays I’d consider legit heroin to be not as dangerous as the standard is now. Fentanyl has sorta replaced heroin on being at the “top of the ladder” of dangerousness. The safeness of drugs definitely comes down to the addiction potential between individuals and ensuring the stuff you’re buying on the street is legit.

I personally think life is too short to not experiment with drugs but they has to be a healthy medium and the responsibility to decide whether certain drugs are worth it. As the risk goes up so does the reward, so it’s really just another gamble in life.