It's bad because the "stock market" that people focus on are typically indices of only the largest companies, such as the S&P 500 and Nasdaq. If the concern is

It's bad because the "stock market" that people focus on are typically indices of only the largest companies, such as the S&P 500 and Nasdaq. If the concern is around performance of these particular indices, it can lead to more policies that favor large business at the expense of the small.