Same reason why they sanction countries, like Iraq, Iran, Russia, and Venezuela. The margins on commodities, like oil and gas, are much greater on the black market. They just need to launder the money.

Price of barley. It came down to the price of barley. Its pretty simple, but not intuitive.

The only way to plow a field of grain before tractors were invented was to hitch a plow to a horse. A person could plow by themselves or with mules but draft horses were the most economic solution. There were a million family farms in America and they had collectively millions of horses.

Barley is a staple grain and a major component of horse feed and the primary ingredient in beer. You can look at a circle of energy use from before the tractor, people farmed with horses, and used the crop to feed their horses, themselves, and sell the remaining food. Even if they themselves didn't grow barley they would need it as horse fodder because they had to plow.

But once the model t came out, people started putting their plows on cars. It had headlights to work before sunrise and after sundown, it never got sick or tired, and it didn't need fodder. Just to stay competetive everyone had to buy a tractor, and this was detrimental to crop prices, land prices. The shortfall could not be made up by drinking more beer and the horses were never coming back to the fields. The barley they would have eaten would still be grown but might not find any consumers.

People panicked and demanded Prohibition. It didn't work anyways since the farms report literally caused the crash in 1929.

Female social justice warriors were used (recruited in churches) as a front.

Who benefitted were mobsters who ended up controlling the industry.

One brewer, Hamm, survived prohibition by selling Coke and soda drinks and to keep him from competing after prohibition was lifted, the owner was kidnapped and extorted by the mob.

https://growlermag.com/a-hamms-ransom-how-the-kidnapping-of-one-of-st-pauls-most-prosperous-brewers-reshaped-a-corrupt-system/

They were jealous of men being happy