Ancient society often divided people into three types. The first is that the upper class are all royal officials, and the second is monks, craftsmen, doctors and so on. The third kind of people are inferior.
There are many sayings about dirty work. Generally speaking, it is "one player, two pushers, three turtles, four turtles, five shaved heads, six back rubs, seven prostitutes, eight thieves and nine blows". There is also a saying that "a wizard, two prostitutes, three gods, four bangers, five shaved heads, six hand-blowers, seven performers, eight street prostitutes and nine candy sellers".
So if we look at this classification roughly, we can find that there are actually three kinds of low-income students. The first is coolies. The ancient labor force was the least valuable, and people without any skills could only earn money by coolies.
Therefore, people who shave their heads, take a bath, become officials and sell sugar all rely on their own efforts to complete the work. And this will be rejected by the upper class. Be assigned to the lowest class.
The second is a liar. Witches, for example, are liars. Basically, it is to attract business by mouth, but this witch is not credible. The ancients were very taboo about this, so they got the lowest score.
The third kind is people with low moral values. Like prostitutes and turtles. Needless to say, prostitutes refer to men who work in brothels, and thieves are thieves. This is the most despised and naturally classified as inferior.