So do you take Benadryl recreationally? I think you're missing the point that some drugs are useful for things, but aren't habit forming, therefore it's easy to walk away from them when you don't need them anymore; thus you remain in control. Other drugs typically get regulated in some way because they ARE habit forming. The user of the drug expresses the desire to stop using the drug yet doesn't have the willpower. Cigarettes are a great example of what happens when an addictive drug goes largely unregulated. Look at the strain on our healthcare system caused by long term smokers. If you care about other people lying in a hospital bed drowning in their own fluids, you might say this is already tragic. But if you don't, just look at what is coming out of your pocket to subsidize the healthcare of smokers. Every time you pay your insurance premium, you are subsidizing those who can't pay for it themselves.
Getting back to pot, maybe the risks aren't the same, but you can't say there is no risk. So look far into the future you are arguing for, and imagine what might you be forced to subsidize for those users who can't or won't stop?