Why was the period between 1919 and 1929 considered a renaissance?

It was not, and nobody really considers it a "renaissance". 1919 through 1929 was a period of frantic but unsustainable growth in the economy, fueled more by speculation rather than any economic fundamentals.

It coincided with the first decade of Prohibition, in which the sale, possession or consumption of Alcoholic Beverages was forbidden by law. It may be that the illusion of rebirth or renewal was prompted by the poisoned illegal booze that people were drinking.

Prohibition was a uniquely spectacular failure as a public policy; it prompted flagrant and widespread disregard and disobedience for the law, and fostered the explosive growth of organized crime. Some of America's most notable families got their start in flouting Prohibition. Joseph Kennedy, the father of President John Kennedy, established the Kennedy fortune by smuggling alcohol into the United States.