Remove one sport from existence

Hurling.

Another vote for basketball.

American Football.

Imagine how good either code of Rugby could have been had the US simply kept playing those rules instead of inventing their own.

Basketball was the one that popped into my head when I read the OP.

More straight to the point to say which should exclusively continue to exist : Association Football & Ice Hockey, that's two, I know.

Although, apart from NFL, I think if you make an effort to really follow and get into any given sport there is a chance you may grow to enjoy it. NFL flowing action never lasts more than five seconds but I haven't watched more than the clips on the news so I ain't an authority on it. Stop-start-stop-ads-stop-start-stop-long break-ads ad infinitum... but, you know, millions of people get pleasure out of watching it. It depends what you grow up with.

Tennis has gone to sh*t (although table tennis is exciting, even if points are won in two seconds flat, the reactions can be breathtaking) cricket is for extreme enthusiasts, bowling looks like dead people walking, wrestling is vaudeville, boxing/kickfighting are brutal and an insult to the name of true sport - karate/judo, yes, I would say these are sports because they are about outwitting your opponent with more than just a bloody no-holds barred bloodfest. 

Then there's chess. If there is a 'sport' for the brain here it is, but the stamina, physical stamina, needed to be sat there in one place for possibly hours at a time while maintaining a high-running brain flow, takes some doing. I'm split on chess, I have to say.

I think swimming is definitely a sport. A lot of physical exertion involved and the action is non-stop. Running, all that, yes. Darts, snooker, poker - forget it. What I'm trying to say is that a lot of things pass for sport these days and it's quite difficult to evaluate what constitutes sport and what doesn't. I remember that pathetic and shameful event at the London Olympics called Dressage, which involved cruelly 'trained' horses prancing around like ballet dancers one minute and standing stock-still the next, all the time pompously mounted by the sort of subhuman who wouldn't know the difference between the RSPCA and a McDonalds slaughterhouse. I'd never seen such a disgraceful public exhibition going under the name of sport.

So many 'sports', we could be here till Christmas, impossible to really pick one unless you have seen them all with some consideration, which mostly I haven't, but...

Answer : Dressage (and that includes show-jumping, pony trials and greyhound racing, and any other so-called sport that involves animals) 

Bullfighting or maybe tomato throwing. Yeah bullfighting

Thats if they call it a sport.

Lots of white people saying basketball, lol.

Anything that ends up with something being killed without being eaten.

Cricket spitting

I gotta think that anyone who doesn't name some obscure sport that nobody cares about is being disingenuous.

Basketball? Maybe the best sport on Earth? Sure guys. Pick one of those worthless sports like Curling or Cricket instead.