I had to go the the circus this afternoon for a work thing. It’s probably been the better part of two decades since I’ve been to one, so my perspective has changed a bit. (Namely, “Ooo, tigers and elephants!” is no longer my primary thought. Though they are neat.)
I have a hard time believing that the animal portions are particularly justified. I’ve read posts by Jerry Coyne (which I don’t care to search out) where he has said he dislikes zoos and (if I recall correctly) is against them. 
I don’t go quite that far because, while improvements can always be made for general and specific conditions, I can see the upside. The animals have food and shelter whilst simultaneously providing a great learning experience for the public. Circuses, however, don’t come with that benefit. They certainly provide food and shelter, but there is hardly a decent learning experience to be had. What’s more, I find it impossible to believe that some of the animals – especially the tigers – aren’t under a load of stress.
For the Sake of Science 
It’s the clowns I worry about. I’ll share a story for you about a particular clown — who was almost certainly the one you saw at this circus — when we go on our hike.