The idea here is that ice is to be treated as food. You wouldn't store raw chicken mixed in, or in contact with cooked hamburgers.
Same thing for ice. You don't want to use that ice you had in the cooler keeping raw meat cold and then use it in a cocktail.
Who really knows what's on the outside of a can? The chicken probably didn't bleed on the ice. These are just saftey precautions.
Nothing wrong with using clean ice at all.
Hope this helped.