Their opponents think maybe protecting local distributors and producers is a more likely explanation. Using children as an excuse for passing get-tough regulations is a tried and true approach. It's also a little hard to swallow this time. Stealing a drink from an unlocked liquor cabinet is both easier and cheaper than ordering and waiting for an expensive bottle of wine. Youngsters are surrounded by access to alcohol in our society, and the Web won't add to the dangers they face.
Wineries are strongly opposed to any efforts to curb online alcohol sales.
Shopping for wines directly saves money and gives consumers the chance to buy what they really want rather than what they can find. If I order a nice bottle of Californian wine direct from the winery, the moral independence and authority of my own state won't be devastated in the process. If I lived in a state where alcohol was banned entirely, I could understand legislators being upset, but that just isn't the case. Alcohol is legal, and they just want to control what hoops we have to jump through to buy it. Maybe one of the lessons that the Web can teach is that jumping through hoops is annoying.