Why must I be of legal drinking age to enter a liquor company's website?

Any time I go to check out the website of one of my favorite purveyors of intoxicating spirits, there is some sort of disclaimer that states that I am not allowed into the site unless I am of legal drinking age. Why is this? I have never noticed any lessening of my sobriety during the perusal of such sites.

I imagine they’re trying to avoid being liable in some potential lawsuit that would claim they intentionally advertised to minors, a`la cigarette makers.

Yes, they must make at least a token effort to avoid charges of marketing to minors. After the Joe Cool fiasco, I’m not surprised.