This is why I prefer to use the term "kink" or refer to something as "fetishistic" rather than refer to it as a fetish per se, as classical sexual fetishes tend to be a lot more than a passing interest and much more deeply integrated into the person's personality. Mostly people know about these through extreme, socially unacceptable examples, but it can be so small and peculiar as only being able to have sex with the lights off, or while wearing a particular article of clothing. A kink is simply something which enhances the sexual experience which is not conventionally or inherently sexual. At least, that's how I see it.And in the (classic) psychological sense a fetish is an object, without which, the person can not achieve sexual satisfaction/orgasm; it's not merely something of interest, but something deeply hardwired into the personality, that (almost) always has to be there for arousal/climax to happen at all. Today, the term sees a more relaxed usage, and we are free to sample fetishes which might appeal to us, so much like candies from a dish.
Kudos on citing Krafft-Ebing, by the way. He, Havelock Ellis and Magnus Hirschfeld really laid the groundwork for modern sexology as a science, and were all quite progressive for their time; hell, some of Hischfeld's work on gender identity is pretty radical even by today's standards.