I honestly believe that one person's "perversion" is another person's "normal" and vice versa of course. Obviously there is stuff which is less common (or so we are led to believe by surveys and such) than readily accepted practices, but why, providing both parties readily agree to whatever it is, should other people deem it wrong - period.
Wrong for them is quite understandable and acceptable but I don't think anyone has the right to condemn someonme else's sex life. At the end of the day, what does it matter if Mrs Miggins down the road enjoys something you might personally think is odd.
And I'm convinced that a much larger proportion of people than you imagine have their own little "peculiar" fetishes. After all, the ins and outs (no pun intended) of our sex lives aren't something that most people would probably be totally honest about, me included, simply because many people (even "adventurous" ones) regard such things as private and personal.
I don't give a damn what other people do - honestly - even if it's something I'd never want to try in a million years. I'm a great believer in the old adage "if it feels good do it" (providing no-one gets hurt - either emotionally or physically (unless they want to be!)).