Here's My sources
http://elderscrolls.wikia.com/wiki/Lefthanded_Elf
http://www.uesp.net/wiki/Lore:Lefthanded_Elves
Firstly they did defeat the Elves before Yokoda had sunken but not "Wipe" them "Out". Actually there no proof stating that the Redguards completely killed all of the Elves, also the Redguards are blamed for the Destruction of Yokuda (which is believed to the reason of the extinction of the Elves.) not committing Genocide.
The sources I've displayed both show that the only skills the Yokodans have shown to have we're taught by the Elves such as: Blacksmithing orichalc, making Scimitars and Seafaring. Especially ruling land and surviving desert-like environments.
Also a word of advise don't going around trying to correct everyone for small things like a smart ass especially minor mistakes in wording or sources! That kind of behavior morally acceptable by society and a horrible wake to NOT make friends and make bad reputations.