Did he downplay the dangers of it? No. Did he give false information about it? No.
What did he say, exactly? Well, he said, exactly...
"As has been well documented, I smoked pot as a kid, and I view it as a bad habit and a vice, not very different from the cigarettes that I smoked as a young person up through a big chunk of my adult life. I don't think it is more dangerous than alcohol." (emphasis mine)
As a follow up question, he was asked, "Is it less dangerous?" (emphasis the interviewer)
Less dangerous, he said, "in terms of its impact on the individual consumer. It's not something I encourage, and I've told my daughters I think it's a bad idea, a waste of time, not very healthy." (emphasis mine)
No downplayed dangers, no false information.
However, we now get a handy-dandy, just-in-the-nick-of-time study that shows heavy, chronic pot smoking during the teen years of neurodevelopment causes brain underdevelopment. And, it immediately gets reported as "smoking pot causes causes brain damage for life," even though that's not what the study shows at all.
Did you know that heavy, chronic alcohol consumption during the teen years of neurodevelopment causes brain underdevelopment, toooo?
That study used people diagnosed with cannabis use disorder, which is defined as being cannabis dependent requiring treatment. It's the same thing as being diagnosed as an alcoholic.
70% of American adults always drink at low-risk levels or do not drink at all. (Thirty-five percent of Americans do not consume alcohol.) About 28% of American adults drink at levels that put them at risk for alcohol dependence and alcohol-related problems.
50 percent of people who start drinking before age 14 become alcohol dependent. When they start drinking between the ages of 14 and 21 the numbers fall to 28 percent. If they start drinking after age 21 the number falls to 9 percent. The numbers for cannabis dependency are 9 percent across the board, regardless of the age they first started smoking pot.