I think that many of the comments here are very valid, including the jokes - as sometimes black humour makes it easier for people to deal with terrible things.
But do consider that it is well documented that by exposing children to animal cruelty you start a desensitisation process that affects the development of empathy and nuturing. As humans, since the domestication of animals about 14,000 years ago, we have built a relationship with other species whereby our children can learn to value their environment, value each other, understand and care for the feelings and emotions of others, gain nurturing skills and a sense of responsibility throught their contact with animals.
Children follow the lead of adults. I loved the circus as a child, wanted to run away and join it and that love and passion led me into my own career. I later discovered that the circus I had loved so much was responsible for a great deal of cruelty. Nevertheless, I would not like to deny any children the delight and magic that a circus can bring. But all it takes is a well informed adult to use it as an educational tool to make a difference. People learn through challenges and children thrive on it.
Whatever anyone says, it is not OK to treat performing animals in this manner. I also agree with a previous poster that it is not OK for food animals to be treated with cruelty either. It is also not OK for us as a community to pretend that it is OK, just because people are enjoying it.
I have to add here that we must also remember that public spectacles that caused delight throughout history are considered barbaric and unacceptable now. I just ask people I meet if they have thought about the way the animals are cared for in that particular circus. Most haven't. When they do, it usaually makes them think differently.