Play enough chess and your ego will take a beating. Unless you are the world's best player there is always someone better than you and even then, someday, there will be.
Are there egotistical chess players? Sure. Are they any more numerous than any other player in any other sport (as a percentage of the players). My guess is no.
Simple question. The only other game or sport that I think can compare to the egoism in chess is perhaps boxing, and it makes sense as being on the opposite side of the spectrum(mental/physical).