It depends on why they are working. I am one of those you asked about. I work because I have a very good and well-paying career as a legal editor that I love. I've been here 28 years as of next week, and I will have a good retirement when I do leave. Many of the people in this state agency work well into their 70s. One of our editors is 79 years young.
The older workers that I find sad are the ones who are having to work to stretch their meager SS pensions, like the Walmart greeters. However, I'm not quick to judge them because some of them love their jobs, too. They find that they are too lonely and bored staying at home, and interacting with the public is stimulating to them.
There is a state organization that matches older workers with companies. Many companies prefer older workers because in addition to being skilled employees, we show up for work with little absenteeism, do our work, don't text or talk on the phone all day, and aren't frequently taking off because we are trying to raise small children.
Many people my age who don't need the money are doing volunteer work. The pitiful ones are the ones who want to stay at home and dry up. Or as Tamara says, those who have to work to support their grown children or grandchildren and would rather be elsewhere, like traveling.
Please don't sell us short, young man.