There's risk as measured by volatility. This is exemplified by the stock market - it's highly volatile, but has a higher expected return than the bond market. People who can't afford the risk of the stock market (because it's too volatile) put their money into the bond market, which has less expected returns.
There's risk of not meeting your retirement goals. There's risk of unemployment. There's risk of permanent loss of investment. There's risk that you can hedge with insurance.
> rich people there is very minimal risk since they usually have a safety net to fall back on.
Rich people have minimal _overall_ risk because they can afford to take large risky bets with positive expected return. This is because they have so much capital they can afford to take these bets over and over until the reward arrives (Kelly criterion). Poor people can't afford the risk, and therefore have to do things like pay for more insurance coverage, pay for extra warranty, or have a (relatively) large emergency fund.