I grew up super straight-laced, but my neighbors in college were daily pot smokers. I asked them about it, they were really cool about talking about pot, how much they used it, why, etc. Then I asked them about cocaine, and they were shocked, stunned that I could even enter coke into the same conversation. "That drug is evil!"
Within a week, I asked the same question of a DJ, a friend of my roommate. He had the same reaction; here was a guy who deals drugs, but he wouldn't even look at coke. He was baffled at the naivete of my question.
It was the first time I realized that there were degrees to which people would go, in doing drugs. I had always thought it was an either/or situation, completely binary.
In summary: even dealers and constant potheads think some stuff is just bad, and cocaine is one of those stuffs.