No, it just explains that Polynesians that make up nearly half of all NRL players, prefer to play RL, not AFL. Polynesians make up 0.3% of AFL players. On the flip side, Africans for some reasons, play AFL but not RL. Both codes have a similar number of Indigenous players, and players from other backgrounds.
The origin of immigrants in Sydney v Melbourne v Perth/Adelaide/Tas (very white) also helped explain the difference. Half of Australia’s Polynesian population is in NSW. Vic and QLD have similar number and there are hardly any in WA/SA/Tas. Perhaps is is no coincidence that they move to the ‘Rugby States’. There are simply very few Polynesians playing AFL - that is why they do not get drafted. Don‘t worry, if the AFL got a whiff of an Islander kid showing potential they would roll out the red carpet just like they did with the failed recruiting of Falou and Hunt.