Actually, people who have done controlled statistical studies have not found this. But one could easily get that impression from fora like this one. I believe that this is a case of reporting bias.
BDSMers as a group are more self-aware and articulate than average (this is borne out by quantitative studies!), and clearly feel safe revealing their feelings in places like this. Therefore, you will find more people reporting a history of abuse than you would in vanilla circles, even if the actual number of abuse survivors is no greater than average.