Urrh, actually the large majority of pages that size who are promoting affiliate links DO use FBML (with the javascript codes).. but it is because of those codes that they normally get banned fast.
Facebook don't watch over the older groups as much as the new ones, well when I say Facebook, it's either the employees or some bot they have created to find risks, or find out based on the page reports, anyway that explains why newer pages building up fans fast go down faster than the slow but steady buildup page.
It's really not ridiculous, to an innocent english speaking Facebook employee, trained to hunt down a run of the mill spam page and ban them.. Well, as this page is in french, and to be honest doesn't look like the "normal" spammer page, it does slip threw the gaps quite easily - though I am quite sure it will be taken down in the next few weeks/days if it continues to push affiliate offers.