I think that your negative view of alcohol is making you a bit conspiratorial. It's an extremely deeply ingrained thing in western culture, you don't need to resort to product placement to explain why filmmakers depict it. People genuinely do have a good time drinking.
People enjoyed drinking long before there was marketing. People have been enjoying alcohol for literally tens of thousands of years. It has been associated with celebrations for many thousands (e.g. Jesus giving people alcohol to keep a wedding reception going - and that is just something that comes to mind - I am sure there are MUCH earlier examples someone familiar with older stuff can come up with).
I would correct it to anti-alcohol sentiment being ingrained in American culture (as it is in some others, such as the Middle East) rather than western culture. Its an American hang-up, as with nudity etc.
Alcoholism was so rampant in the US that enough states ratified a constitutional amendment making it illegal.
It wasn't enough to kill alcohol consumption entirely, but it did cut back on the culture of overindulgence as measure by death rates before and the years after.
Other countries also banned alcohol in this time period, and new Zealand voted for it twice but never enacted the ban.
