I think sharpshooting was not featured at rodeos because cowboys were mediocre shots.

yes

Annie Oakley - 1954 Sharpshooting Annie 1-23 was released on:

USA: 12 June 1954

Because it's very dangerous. the definition for sharpshooting is; one skilled at shooting. rodeos may be crazy but it's also safe. you wouldn't want to see a person OR an animal dying just for your entertainment.

It's used solely as a sniping/sharpshooting weapon. If I remember correctly, the full auto feature was removed from the original M14 rifles which were converted to EBR configuration.