Alcohol toxicity can produce brain damage and even death for anyone, of any age. Why isn't it simply outlawed?
You know that brain damage and death is caused by immoderate consumption, which wasn't what I was talking about.
When the brain is still developing it is extraordinarily sensitive, and I take the better-safe-than-sorry attitude. If people decide to kill themselves with binge-drinking after they're fully grown, that's their decision, made with full adult cognitive ability.
Is it meaningful to put an age minimum on alcohol consumption/purchase?
Seems it varies a lot around the world- from alcohol being completely illegal to it being completely legal, but for the most part the legal drinking age barrier is set at 16-21.
I'd say it's good to have, simply because it discourages people from getting addicted earlier in life. They can still get alcohol regardless of the law, but it's a deterrent, especially for the more compliant ones who are likely the ones they really care about protecting anyway.
Having an age limit rather than total prohibition effectively disinclines more of the adults from helping the kids get alcohol, and allows them to bask in a feeling of superiority that encourages them to help enforce the law. If we had total prohibition, it would be everyone who wants to drink vs. the government. This way, the adults and kids focus their envy/frustration each on other as they do on many other issues (since there's already an inclination towards cross-generational strife) while the government and law enforcement bow out of the picture.