What is wrong with the undercutting on this server?

Here is an example of some items being sold.

Item X

sold : 10,000 g
sold : 10,000 g
sold: 8,000 g <---- BAM why do you need to under cut 2k?
sold: 6,000 g <---- #$(&!!!!!!!!!!




I don't get it why do people on this server like to make less gil then they can?