Safe, if you avoid mentioning doping, the effects of concussion on the brain, whether it is ethical to ride horses (more so to jump fences and to use a whip), the ethics of nations training 4 year olds for gymnastics, the fairness of juries in boxing/gymnastics/dressage, whether a sport should be in the Olympics (for example, where are the motor sports?), whether we should have separate events for lesser abled competitors (Paralympics, but also weight classes in judo, boxing, rowing, etc) etc.
For example, if I state gymnastics isn't a sport, just as ballet isn't, and that watching it means condoning child torture, is that a safe bet?
(Edit: and that's ingoring the really contentious subjects such as whether England really scored that third goal in 1966)