Just like you can drink wine responsibly, you can smoke responsibly. I don't think you can do heroin responsibly.
I'm not ok with being stripped of a wide variety of possible enjoyable experiences just because somebody is going to abuse them.
An estimated 65% of people who inject heroin don't develop an addiction compared to only 20% of cigarette smokers [1]. I wouldn't bet my life on these exact numbers but everything I've read suggests that occasional heroin users exist [2] and may exist in similar proportions to occasional smokers.
You mentioned cigars, which might be different, but the original article is primarily about cigarettes.
Again, I'm not endorsing anyone smoking or using heroin, nor any particular policy. I'm just bringing up some findings that contradict the idea that responsible use of heroin is much less likely than responsible smoking.
[1] https://www.bakadesuyo.com/2012/08/whats-the-most-addictive-...
[2] https://amp.cnn.com/cnn/2018/02/27/health/functioning-heroin...
Why not, out of interest?
It's not like information about heroin is hard to come by.