Interesting idea! I'm curious on where your theory came from or if you have any examples that come to mind.
First, my POV is that "intelligence" is a slippery thing in the first place. Someone with a high IQ might be a total failure on the social scene and not come off as very smart. Someone who doesn't do well on tests might have great presence, charm, and adaptability to real life situations. You know what I mean?
Having said that, I do think that people who are more comfortable and confident in themselves are more willing to be open about their fetishes. And I find self-reflection and self-understanding to be VERY intelligent!!