There is a trade-off between freedom and keeping people safe, and there is an argument for some level of personal responsibility. I’m glad that I can drink alcohol once in a while without becoming an outlaw, even though I know the effects aren’t harmless.

I also disagree with the dehumanization argument. Yes, the concrete age limits are a bit arbitrary, and actual maturity depends on the individual and is a spectrum, but regulations necessarily have to come with some level of pigeonholing. The fact that you may have to show your ID when buying alcohol isn’t dehumanizing.