I grew up around metals and machine shops and learned professional nomenclature at an early age. Although aluminum has been around for a while, the amazing alloys, machining technology and techniques have not. Many people seem to have some sort of prejudice toward aluminum, specially in US. I would imagine that use of the word alloy happened through trying to avoid the use of the word "aluminum".

Case in point, one of the posters in this thread wrote "aluminum cans have no structural integrity" but really, few if any aluminum cans are engineered to support the weight of a person when empty and few if any have failed when used as designed. They are cheaper to produce, last longer, more sanitary and are cheaper to transport and can be stacked just like cases of steel cans. It's a typical perception.

If you look at a 70's harley davidson motorcycle (100% steel, 700 lbs, very poor performance) and a Euro/jap motorcycle of the same period (400 lbs, lots of aluminum) it's easy to see that sellers of steel have worked hard to make aluminum undesirable from a marketing perspective.