Because using "chairperson" and "salesperson" doesn't go far enough to establish gender equality.
Here's a representative sampling of entries:
APERSONS, interj. term used to notify the Deity that one's prayer is finished.
DEPERSONDS, n. humble requests made to the powerful by oppressed minorities.
GERPERSONY, n. a pacifistic country in Europe divided into two parts known as East Gerpersony and West Gerpersony.
ROPERSONTIC, adj. (1) characteristic of the delightful atmosphere favored by real and would-be lover; (2) characteristic of the notion that the good persons will always win.