Minimum legal drinking age laws are largely an invention of the early 20th century, and still do not exist in many nations in Africa and Asia. The United Kingdom did not have a national minimum drinking age law until 1923, when the Intoxicating Liquor (Sale to Persons under Eighteen) Act was passed due to the advocacy of members of the temperance movement, which had declined by the mid-20th century. Given that drinking age laws have little effect on underage drinking, and that many nations (past and present) have gotten by without them, these relics of the legal past should be abolished.
[P1] Drinking ages are a reasonably recent invention; society got along without them for a long time. [P2] Drinking ages are pointless, and we do not need them.