I do agree with this, though many people I know are dead set against it.  For me, though, the statement released by the initiative provides all the justification I need:

…adults under 21 are deemed capable of voting, signing contracts, serving on juries and enlisting in the military, but are told they are not mature enough to have a beer.

Many people would put the limit at 19 instead, so that high school seniors would still be limited.  And there is merit in that idea.  I would go a step further.  19, I’m okay with… but anyone, even 18-yr-olds, with a valid military ID.

Is it right to confer special privileges based on military service, in this way?  I think it is.  I’m all for rule of law, but simply put, if you can kill and die for my freedom, you can drink if you want to.  Hell, show me a military ID, I’ll buy you a beer just to say thanks — whether some stiff in a suit says it’s okay or not.