Alcohol and tobacco advertising is banned or massively regulated in most countries. Facebook circumvents rules in various places due to their media platform being newer than the rules or because Facebook just sort of ignores the rule.
https://en.m.wikipedia.org/wiki/Regulation_of_nicotine_marke... https://en.m.wikipedia.org/wiki/Alcohol_advertising https://tobaccocontrol.bmj.com/content/28/1/67
It’s not hard to find good sources stating Facebook still advertise tobacco, though you appear not to have noticed the links stating this fact. Here are some more recent links.
https://www.theguardian.com/business/2020/mar/17/british-ame...
https://www.independent.co.uk/health_and_wellbeing/big-tobac...
“British American Tobacco circumventing ad ban”
“Smoking giants are flouting rules set by Facebook and Instagram”
As always, regardless of the digital or print medium, Big Tobacco (& others) have always tried to flout the rules. Same goes for Alcohol and Gambling ad bans.
Yes, it’s proving hard to enforce a ban, but are we supposed to be sympathetic to Facebook?
‘On Instagram, Big Tobacco’s influencers post glamorised images of vape products with hashtags such as #idareyoutotryit and captions such as “feeling Vype AF”.’ (From my link).
https://www.independent.co.uk/health_and_wellbeing/big-tobac...
Ads cost money, why is it in the public good that I spend money to bother people with ads they'll never take part in?