Why Did Facebook Yank Marijuana Ads?

Although Facebook claims to have removed the pro-marijuana legalization ads so users wouldn't, you know, get baked, public health might not be the real reason. (Shocking.) As Valleywag reports, Facebook, quite possibly, wanted to keep the site "attractive to big spending, blue chip ad clients who don't like their campaigns surrounded by seedy looking pro narcotics narcotics ads." Major buzz kill. [Valleywag]