You aren't a drug dealer, you're a pot seller.
To you, pot seems like what everyone is doing because you are accepting of pot users. But, do you think someone you know is going to tell you they do something like go home every night and shoot heroin when you use names like "Junk Box" to refer to those people?
I had the same experience. I sold pot to zero out my pot budget. Everyone I associated with had a cavalier attitude towards pot use but looked down upon those who did "hard" drugs. Those who used pot weren't shy about admitting it so it seemed like that's all anyone was doing to me too.
But then we got the opportunity to get extra credit in HS for community service. I chose one that was just setting out doughnuts and making coffee for a couple hours on Tuesday nights. It turned out to be meetings for The Fifth Chapter Motorcycle Club (and being it was a small town, they also hosted Narcanon members). It was a great experience with great people so I kept doing it for about 5 years before I moved from the area.
In there I saw hundreds of people who were doing coke, crack and meth daily for years. Many were people I knew (small town) and would never have suspected was a junkie. And I know for every person I saw in there getting treatment, there was likely 10 more in the community doing it who weren't.
Just because you like to think of yourself as an expert, you aren't one. Neither am I. But I spent a lot of time around people who were and know I wouldn't ever want to be an expert on that world. But through them, I got a glimpse of the real world and it's not pretty.
Which is why I have such a huge problem with the criminalization of drugs. It's designed to stop people from using them but it fails miserably at that. In return for nothing, it creates a black market exploited by violent criminals, it glamorizes them to youth (just about everyone who was in treatment started when they were young and did it because they were told NOT to) and the worst thing to me is that it adds a stigma that prevents those in the real world who have seen the bad side from sharing their experiences.
I've never done any drug besides pot and the reason is that I was exposed to the realities of other drugs. No one believes someone brought in by the school or cops to make speeches or people on TV Commercials. But when you see a 350 lb wall of muscle, who is someone you know from your community, sitting on his Harley laughing as he shows you the places he's been stabbed and then is in tears 20 minutes later telling the group how Heroin made him it's bitch, you figure out that it's not a question of being strong enough to handle it; It's being smart enough never to start.