Low interest rates mean less income to these individuals. The stock market is too risky for these individuals to invest in at this particular time in their lives. Senior citizens typically do not have the time to recover from a downturn in stocks. As a young person, if you invest in the stock market, and the market takes a nose dive, you have years of earning potential to make up the loss. A senior citizen does not have years of earning potential to recover from a large loss in the stock market.
Young people like to see low interests rates.
They are typically buying homes, automobiles, furniture, etc. Young people must often use credit to acquire many of the items they want because their incomes are not sufficiently high enough. If you are a net debtor, you want to see low interest rates. If you do not have much debt and are a net lender of funds to financial institutions, you want to see high interest rates.