Their coffee tastes the way it does because of how they roast it, it's a purposeful style thing (that tastes terrible and is horribly overpriced imo).

Their roasts are also darker than they say. Everything they have is dark roast, with their 'blond' coming in closer to a medium.

People go nuts over the sugar, caffeine and perceived status, it has nothing to do with the taste of the coffee. As a fellow black coffee drinker, my recommendation is to avoid Starbucks unless you happen to be near a union store where the coffee is guaranteed to taste more like freedom, but still like ashes soaked in oil.

In case you want more details: The way coffee roasting works is you move beans around in a real hot container, and you try to keep them to a specific point on a temperature graph at each moment as they roast. A different roaster would roast them a bit slower, but Starbucks just blasts those beans with everything they have, then they don't stop until the beans are burnt. This gives them their "signature taste". This is largely because of Howard Shultz, the guy who drove the company to be a cafe, and until recently the CEO. That's his preferred coffee taste and that's what he demands the company makes.