Facebook is a global phenomenon of epic proportions. So why is the site pushing U.S.-centric morals on the rest of the (sometimes more enlightened) world? Case in point: Banning images of a marijuana leaf, which was only being used to spur political debate.

The “Just Say Now” group is a new independent entity that’s pushing for a rethink of the strict anti-marijuana laws in the U.S. at a political and public level. Its members include transpartisan politicians, judges, students, and a whole bunch of other people representing a pretty good slice of society. They’ve got a website, and they mean serious business in the face of foot-dragging on the matter by the usually progressive Obama administration. To achieve access to a wider public audience, the group has also crafted a Facebook page, and received approval for adverts to promote it on August 7th. The advert contained, of course, the most iconic and attention-grabbing image it could–one that’s already well-known to the public: A marijuana leaf.

Then later, with no explanation of why at first, the site blocked the advert.

Investigations revealed that the pot leaf “violated” Facebook’s policy on acceptable images because it promoted smoking, and all pro-smoking images are deemed unacceptable. As are images that promote illegal activity–marijuana consumption is illegal in the U.S. unless under some strict regulations in rare medical situations, so presumably this is behind Facebook’s decision.

But here’s the first problem: A pot leaf isn’t a “pro-smoking” image. It’s a plant, and as many of Facebook’s executive team should know (like 40% of Americans who consume marijuana regularly as adults) there are many ways of consuming the product other than smoking it. Blocking the image on these grounds is “tantamount to banning a candidate’s face during a political campaign” according to a Just Say Now spokesman who spoke to Reuters, since the campaign is not “pro-smoking” but a political effort to change the law.

And here’s a worse problem: The strict anti-marijuana laws in the U.S. aren’t necessarily representative of the legal position in other countries around the world. Take Holland, for example, where the drug isn’t strictly legal, but there’s a famously relaxed interpretation of enforcing the regulations. Or Portugal, a poor and strongly Catholic nation which is leading Europe in a progressive stance on drug legalization: Most drugs have been decriminalized there since 2001. Portugal’s policy has been so successful in reducing drug-related crime as well as absolute drug consumption levels, and has increased the number of people seeking addiction help so much that it’s seen as a model for the rest of Europe. An image of a pot leaf is most definitely not illegal in Portugal. Why can’t Portuguese Facebookers see the Just Say Now campaign? We’ve emailed Facebook to ask.