Asking because I am not sure if Facebook should be making the shots here on what is legal or illegal to advertise. This is best handled through government.
Edit: changed the example
I do agree though and would go further and make it illegal to show ads to anyone whose profile states they are under 18.
You cannot advertise alcohol to children in Australia
A complaint first has to be raised with Ad Standards, who undertake ethical review on a case-by-case basis.
That is, it is generally illegal to market to those who are underage, but it is not generally illegal to display such advertising in a space where those who are outside of the target audience.
The usual legal process is to review individual ads, and those creating the adverts are the ones who end up in trouble. An entire marketplace (like Facebook) deciding that marketing to minors is okay is untested waters, because each individual advert would normally be ruled illegal so why the hell would the market allow it?
[0] https://www.abac.org.au/wp-content/uploads/2021/03/ABAC-Resp...
They even created a new entity (Mission Winnow) in 2018 which is purportedly an initiative “to create engagement around the role of science, technology and innovation as a powerful force for good in any industry”, whatever that means. Conveniently, MW has the same color scheme and a suspiciously similar "M" logo to Marlboro, and surprise, they've been a title sponsor of the Ferrari cars since, though they didn't use the branding in 2020 after countries started investigating whether they were flaunting the ad ban.
Ethically, you often have an obligation to do more than the bare legal minimum in order to not be a horrible person.
There's a huge difference between targeting an age group and the age group being exposed by association.
If you saw ads on the Sunday morning cartoons for whiskey and gambling, you could rightly say they are targeting children.
Ads put on during a football game that targets 25-50 year olds that may happen to have younger viewers != targeting those younger viewers.
Facebook is targeting 13-17 year olds.
For instance if your social media account says you are less than 18 then it should be illegal to show any ad to you.
This will have the additional benefit of internet communication technology companies having to rethink kids as a profit center.
You obviously can't completely ban it, since kids under 18 would still have access to cable TV, and therefore advertisments.
But I could see a system where -targeting- kids under 18 would be banned, whereas advertising as a whole is not illegal for < 18 so long as the advertisements kids are seeing aren't specifically targeted only at minors.