These questions are always silly on their face. Which of life's consumable pleasures are irrefutably harmful in moderation? And which are irrefutably safe in excess? None.
I wonder how harmful consuming excessive amounts of organic, shade-grown, tie-dyed, harmoniously sprouted soy beans would be? Especially when used as a base for lots and lots of, well, "tasty" (technically) soy-lattes!
Now a real question would be to ask whether BAD coffee is harmful (to something other than your senses). The primary function of canned coffee for most folks is drug abuse, and a real point can be made about the negative health effects of crude drug-dependency. I know, I am an addict!

(Anyone here who has abstained from coffee for a day or two and experienced the almost crippling head pain that accompanies it should seriously consider just how silly it sounds to blanketly assert that coffee poses no health risks).
Seriously though, how many people can really savor and enjoy 7 double-shots a day? It is not hard to discern when the threshold of moderation has been broken - it is when you stop being able to truly enjoy something, and simply consume it for consumptions sake. Enrichment, enjoyment, etc are justifiable reasons to for everything we do, and certainly outweighs the possibility of adverse effects in most instances. Where the real health dangers have arisen is from absolutely silly attempts to take enjoyment out of the equation so that moderation need not be heeded. Think margarine, aspartame, and the like.