This poster at Huffington Post says it best:
The dismissive answer that the President gave to the questions regarding pot laws shows a willingness to stereotype the issue as one of Cheech and Chong pushing for the legal right to get stoned and be lazy. The truth of the matter is that the prohibition like laws against pot affect the entire country. Families are without parents due to jail time imposed for simple possession, this leads to lower incomes for these families even after time has been served because of the permanently attached criminal record. Prison overcrowding is a big deal in this country and we currently incarcerate more people per capita than any other country in the world, even China. Drug violence on the Mexican-American border is only increasing and this affects hundreds of communities on both sides of the border, on a personal level. The sheer amount of money spent on the war on drugs is overwhelming, even though supply has not diminished over the last few decades, instead it has increased. To ignore all of these issues and a host of others to get a laugh is a cheap oversimplification of a very serious issue for families and communities. I had hoped for a more serious approach from this president, at least the ability to have a serious discussion of the issue, I guess it's still too scary an issue for even a popular and reforming politician, who has admitted to using it in the past, to touch. When will we grow up?
Same time though we’re on the edge of a precipice. What would the Cantors of the world do if Obama suddenly went pro-legalization? It’s just not politically viable right now, even if economically necessary. It’ll happen eventually. The seeds are being sown (being separated from the shake, couldn't resist). Marijuana prohibition is too stupid a policy to not one day be overturned.