Why dishwashers are corrosive to aluminum?
I think it is just alkalinity. Unlike many other metals, aluminum is amophoteric, so it dissolves in both strong base and in strong acid. Most dishwashing detergents are fairly alkaline, probably at pH 11 or 12 or so. That and the heat may be enough to corrode Al.  Most other common metals are attacked by strong acids but not by alkali.