I can agree with you, I have never seen aluminum corrosion in our model glow engines yet and I have been at it for many years too.
I wonder how they came up with that. Pure Methanol is really close to being neutral at a PH of 7.0 but not quite.
But PH levels are measured for aqueous solutions (water mixed in it) so a PH doesn't measure out for methanol in its more or less pure state.
Now granted it does start to become slightly acidic as the water percentage increases, but you are talking about something like 12% methanol to 88% water then. But heck with enough water the ferrous metal parts start corroding without methanol anyway.
Maybe someone who is real good at chemistry will chime in and explain it.