Not everyone is a software developer with companies fighting over them. Some really don't have options, and the choice is either get no income and be unable to pay your bills, or get screwed over but get some money to pay the bills.

All of the waiters/cooks/waitresses at a low-quality diner I frequent regularly have felonies for robbery or drugs. Ever since I've been going there I would say the vast majority of new hires have been people who couldn't get a job in other places because of their felony records and lack of education.

When you have a felony a lot of higher-paying unskilled jobs will simply filter you out as being too high risk or likely to cause trouble. So the only places that will hire these kinds of people can get away with crazy tactics like the ones people are discussing in these threads. When your choice is exploitative tactics or literally no other option because the entire market has you blacklisted you are going to take the horrible option knowing full well it is a horrible option.

The reason people take jobs like this is that they don't have other options, often for a variety of reasons. I know that a lot of the people I talk to need the flexible hours due to family obligations. For some these types of jobs are supplemental- they aren't the primary source of income, but provide a bit extra when money is tight.

For some people though there just aren't a lot of jobs available that match their education and experience.

Because they need to. We're talking about unskilled work. You take what you can get. Such companies know there are unskilled workers that will put up with it and take advantage of that.

Because they need the money.

People that are desperate for money are frequently exploited. Whether it's through wage theft, or unsafe employment practices, or simply demeaning behavior.