I think a tit for tat instinct of obeying basic secular Law that Connects with Natural Law should be obeyed however with such a case like Drinking Alcoholic beverages for Underage Catholics, in reasonable circuмstances it is acceptable for a Parent to give their son or daughter a drink.
As for the bit on "giving alcohol to children relatively young to train their modification" , based on experience, if you give a young teen a glass of wine during dinner, it helps them realise Alcohol in moderated amounts is well and not to go overboard(If i worded that correctly Lol)