(isopropyl) Alcohol will dissolve glue and other things inside the phone. i think they only mant to use a drop of it, or rinse it very shortly and dry it off directly after. Isopropyl alcohol is often used to remove the battery from a phone. or help opening it. (not the Fairphone ofcourse).
Ifixit tells its possible to dip the mainbord in isopropyl Alcohol. and is not talking about modules.
this is mainly for if you dropped your phone in saltwater i think.
Reading it now i can understand your misunderstanding. sorry to hear that happened to you.
luckily its only your screen that is effected, and it is relatief easy to replace a screen on a Fairphone.