I guess everyone is entitled to their own opinions. Obviously the Utube video shows some folks may put the wrong fluids in the wrong hole in their diesel trucks or RV's.
I just know as an owner of a diesel truck that uses DEF, I need a step stool to even check my oil. Being 6'1" tall I sure don't want Ford to locate my DEF filler under the hood so I have to pull out a step stool or step ladder to fill the darn thing when I'm in the truck lanes at a Pilot station. Trucker's would get a real kick out of that!
If Ford would locate it under the hood then there would probably be some idiot that would dump oil in it, or put DEF in their oil fill for that matter.
Unless you actually drive and/or tow with a diesel that uses DEF then you probably should not be locked into an opinion on where the DEF fill should be located. If Ford ever decides to put the fill under the hood then I have purchased my last Ford.