[burnished]

Well, I think you're getting close, but you still seem to be coming at this from a place of presumed superiority, mostly due to the separation of fears into 'rational' vs 'irrational'. Part of TFA is that they were not given enough information - is it irrational to fear some one stabbing your eye just because they are also confident that it will be for your betterment? From your water example it is clear also that you've learned that some water is safe to open your eyes in and built confidence in that knowledge - what if you hadn't had those experiences? Where I grew up the water was painfully cold, frequently polluted, and silty enough that I wouldn't be surprised if you got a scratch on your eye from doing that. I learned to open my eyes in the water in a public pool and discovered that I could do so with only minor irritation. If the chemical balance had been different that probably would not have been the case.

I think another perspective that might be helpful is to think of this in terms of the flinch reflex. Anyone can control theirs (this is an emotional process, sure), but the difficulty involves how sensitive they are, how strong the input is, how necessary they deem the action, and how afraid they are of potential consequences. Again, I don't think 'rational' or 'irrational' comes into play here or explains anything extra, I think in your case for example you are probably not jumpy (overly sensitive), and confident that your outcomes will be acceptable. I think the author was probably a little jumpy and was not confident in the outcome of an eye-poke.