This is a rather tame and naive view of fetishes.
There is not a lot of agreement when it comes to the origin and genesis of sexual fetish. To suggest that all fetishes are a result of learned response and conditioning is a simplistic and naive view of fetishes.
In many cases fetishes come from deep within the psyche. Perhaps they are influenced by childhood experience, combined with personality factors. What ever the case, human sexuality is extremely complex.
My comment that this is a tame view of fetishes is based on the fact that the discussion in this post revolves around visual sexual queues (neck, breasts, buttocks, legs, ankles, feet). But many fetishes are not based just on visual clues.
For example, on Medium the author Spanking Theatre has written extensively about her particular favor of spanking fetish. This includes role play, in addition to visual queues.
This post implies that sexual response is linked to overt pleasure. This is not always true. Spanking inherently involves a certain about of pain, that is translated into pleasure, before, during or after the spanking.
Sexual fetish can be very extreme (viewed from outside of the fetish) and complex. There is a lot more in sexual heaven and hell than is imagined in this post.