~snip~
I have never seen gambling advertisements on Facebook, maybe I am not used to using social media for gambling activities because the system will detect and work based on the search interests used by users, so there is an explanation from Facebook about gambling ads that must be understood. Link
https://www.facebook.com/business/help/345214789920228Perhaps you enabled the filter feature for ads, so you've never seen gambling ads on Facebook. Or maybe the group or people you know have nothing to do with gambling, which keeps you from seeing gambling ads. But it looks like Facebook has its own filter for gambling, and Facebook is very selective with the ads that appear on its site.