Yeah a lot of places in the US usually allow minors to drink either in the presence of their parents and/or at home. It’s seen as an overreach to tell a parent how to raise their child and also, if they’re at home or with parents then they’re not out on the road driving. Combine that with a relatively higher drinking age of 21 compared to other countries, it’s considered a pragmatic way to teach kids to be responsible around alcohol. They probably wouldn’t have cared very much in Manhattan specifically because the kids have money for drivers and taxis and they’re walking everywhere. Little to no risk of drunk driving.

The martinis are absurd but again, in a city like Manhattan and wealth like theirs they no doubt have access to some of the most expensive top shelf alcohol and quality bartenders in the world. Those martinis probably don’t taste as bad as the (very few) martinis I’ve tried (that taste like jet fuel/paint thinner).