Cannabis is addictive.  Stop thinking in a singular fashion.  Addictions occur on two fronts.  Chemical and psychological.  It also does harm adolescent development and this has been proven by non-partisan research.  Or has the fact that the research that claims "non-addiction" and "non-developmental harm" are funded by pro-marijuana groups?  What's next, you going to sit there and try to sell how marijuana is a magical cure for cancer? (Despite evidence that it's good at treating symptoms and retarding the progression of SOME types of cancer.) Surely you understand the difference between "cure" and "retard".

As for the "7%" you're quoting, there's still insufficient research to come to any real conclusion about what impact stoned driving has, especially considering people ignore the research of being stoned on motor functions.

Ask yourself: When as the last time a marijuana supporter admitted that it's not as pure as they'd like it to be?