While I agree the end of the comment was a cheap shot; do you not agree that since Conan has no experience with the drug himself, his views are therefore limited?
Not really. He's pretty damn smart too. I expect that he has more interaction with weed than the majority of us. While most of us just see the awesomely fun effects of being high, he sees the damage that it can cause young people, their families, etc. While his opinion is coming from a different viewpoint, it's pretty stupid to write it off as limited without saying your viewpoint is also limited; because it is.