To answer the more general question, it's all to do with the shape. "Ingot" could be used for any square or rectangular medal, even if it's not specifically intended as bullion. The dictionary definition
emphasises "block" and "oblong" (rectangular) shape, though I would also happily include "irregular" shapes, such as the ancient oxhide-shaped copper ingots
, within the definition.
I wouldn't use the word "ingot" for anything round, or even oval-shaped, not even if it was made of bullion metal.
So yes, that website is incorrect in filing those medals under "ingots". Looks like it's just an compositional error; those images should have been copy-pasted to the start of the "Medals" list, rather than the end of the "ingots" list.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis