This is dictionary.com's interpretation of the word sport:
Quote:sport /spɔrt, spoʊrt/ Show Spelled Pronunciation [spawrt, spohrt] Show IPA Pronunciation
–noun 1. an athletic activity requiring skill or physical prowess and often of a competitive nature, as racing, baseball, tennis, golf, bowling, wrestling, boxing, hunting, fishing, etc.
2. a particular form of this, esp. in the out of doors.
3. diversion; recreation; pleasant pastime.
4. jest; fun; mirth; pleasantry: What he said in sport was taken seriously.
5. mockery; ridicule; derision: They made sport of him.
6. an object of derision; laughingstock.
7. something treated lightly or tossed about like a plaything.
8. something or someone subject to the whims or vicissitudes of fate, circumstances, etc.
9. a sportsman.
10. Informal. a person who behaves in a sportsmanlike, fair, or admirable manner; an accommodating person: He was a sport and took his defeat well.
11. Informal. a person who is interested in sports as an occasion for gambling; gambler.
12. Informal. a flashy person; one who wears showy clothes, affects smart manners, pursues pleasurable pastimes, or the like; a bon vivant.
13. Biology. an organism or part that shows an unusual or singular deviation from the normal or parent type; mutation.
14. Obsolete. amorous dalliance.
–adjective 15. of, pertaining to, or used in sports or a particular sport.
16. suitable for outdoor or informal wear: sport clothes.
–verb (used without object)
17. to amuse oneself with some pleasant pastime or recreation.
18. to play, frolic, or gambol, as a child or an animal.
19. to engage in some open-air or athletic pastime or sport.
20. to trifle or treat lightly: to sport with another's emotions.
21. to mock, scoff, or tease: to sport at suburban life.
22. Botany. to mutate.
–verb (used with object)
23. to pass (time) in amusement or sport.
24. to spend or squander lightly or recklessly (often fol. by away).
25. Informal. to wear, display, carry, etc., esp. with ostentation; show off: to sport a new mink coat.
26. Archaic. to amuse (esp. oneself).
—Idiom27. sport one's oak. oak (def. 5).
Now when you relate the highlighted descriptions of the word to the way the RFL treat the game, it all makes sense!