I wouldn't really call this a fetish, just a preference. In my case as a boy, the head was way too sensitive, almost painful when played with exposed, and it was a way of lessening the sensitivity to enjoyable levels. I have been permanently retracted now for years, such that the short foreskin I originally had has atrophied to the point that it won't cover the head any more, and the short cover just returns immediately behind my head, even if I try to stretch it. It's really just what feels most comfortable. My own doctor describes me as circumcised for the purpose of physical exams, and the women I've been with have never known the difference either. So, in the end, is there really any difference?
Please, no religious or political discussion. If you would like to discuss flying, welcome...I LOVE discussing flying... and then there's ALWAYS the subject we all love....