You're kidding right!
I and thousands of people like me make a living repairing corrosion on many different types of metal, but primarily aluminum alloys: 2024, 6061, and 7075.
I'd check your data again.
Make sure you are looking at alloy info and not pure. Each alloy reacts different in various environments.
Alloys are two dissimilar metals occupying the same space you only need an electrolyte to start the process, water is plenty.
Steel and aluminum don't mix either, this is why you use Cad-Plated or stainless fasteners.
Sent from my little magic box.
I have done my research and also have decades of experience with aluminum in the harshest of saltwater environments.
Here, from the very first reference when googled:
"Aluminum owes its excellent corrosion resistance and its usage as one of the primary metals of commerce to the barrier oxide film that is bonded strongly to its surface and, that if damaged, re-forms immediately in most environments.
On a surface freshly abraded and then exposed to air, the barrier oxide film is only 1 nm thick but is highly effective in protecting the aluminum from corrosion."
Most aluminum alloys have excellent resistance to atmospheric corrosion (often called weathering), and in many outdoor applications, such alloys do not require shelter, protective coatings or maintenance."
"Corrosion in Waters
Aluminum alloys of the 1xxx, 3xxx, 5xxx and 6xxx series are resistant to corrosion by many natural waters. The more important factors controlling the corrosivity of natural waters to aluminum include water temperature, pH, and conductivity, availability of cathodic reactant, presence or absence of heavy metals, and the corrosion potentials and pitting potentials of the specific alloys."
Yes, which alloy makes some difference, but not much. I suspenct what you think is atmospheric or water corrosion is galvanic corrosion the result of fasterers that are disimilar and not isolated. Even then, the galvanic corrosion is a slow though ugly process with lots of white residue, but not so much metal loss over time.
Try google. This link will be a start: http://www.keytometals.com/Article14.htm