No-one in my family drinks a lot (mum has only had one drink in her life; at her wedding) and me and my brother were given small amounts of alcohol from the ages of @2: splash of beer in lemonade to make the weakest shandy ever, watered down sherry at my Gran's, 1 small glass of wine with Xmas dinner or a special occasion, etc. Because alcohol was so normal and boring and not as tasty as other drink options like juice, etc., we've never been interested. I've never seen any of my relatives drunk, so we've never associated alcohol with getting blotto. For us, we saw it as something that used to make our grans fall asleep on Xmas Day and snore through the TOTP Xmas special!
Everyone knows that the things that are seen as forbidden in childhood become glamorous and exciting to teens. All my peers who were obsessed with getting drunk and ending up having fights, sleeping with unsuitable people, hurting themselves, etc., whilst drunk, were the kids whose parents had been really strict about banning stuff, especially alcohol. Me and brother never even got truly bladdered!
I've been teetotal since I was 21 because I think booze is gross and that getting drunk is boring and a bit immature. My brother goes months without a drink and even then it will be just 1 glass of wine, for example. My ILs took the same attitude with their sons and DP and his brothers don't really drink (DP has about 4 small bottles of cider a year).
Food filled with additives - aspartame, for example (found in diet drinks), is very bad for you - and which is highly process and filled with loads of sugar and fat are far worse than the odd sip of alcohol for children and yet most parents wouldn't think twice about 'treating' their DC with junk now and then (or even often). And I'm not judging that either, just being logical :)