Answer:
He saw Gilded Age as a way to mask America's real social problems. He believed that the result would be a strong concentration of wealth, high social inequality and an increasingly violent exploitation of the poor class.
Step-by-step explanation:
The Gilded Age was an era of expansion of the American economy, which showed more promising results than those of the economy in European countries, even to the point of attracting European workers to the country. This economic growth was the result of the success of the railways, mining and a successful system of factories.
However, this caused the emergence of two very distinct social classes, a dominant class (represented by big businessmen) and a dominated class (represented by workers). Howard Zinn believed that this would create a great social imbalance, causing an accumulation of wealth in the ruling class, while the dominated class would be increasingly exploited and would have a very low quality of life due to strong social inequality.