Cheering an injury is quite distasteful. But then again most of the biggest paid professional atletes are boxers and fans cheer as they beat the crap out of eachother. Then there is rugby and football where the whole point is to smash your opponent. Then we have icehockey where fans love the players who fight and it's all by encouraged by the NHL. Finally, we have nascar where I think the point is to cheer accidents.
Basketball isn't a contact sport, though. However, he is paid enough money to deal with the trauma of people celebrating his injury.