Starbucks' roasters are extremely proud of their techniques, too. They're all mysterious and secretive about how they do it, or at least one of their VPs was when I talked to him about it a decade ago. I think they're aware that coffee enthusiasts generally find it to be bad but didn't find that to be a negative to their business. You're probably right that it's because that bitterness goes well with sugar.
That actually holds true for coffee in parts of Asia, too. If you buy from a street vendor in Vietnam or Singapore, to name two, you get some cheap-ass Robusta mix that was roasted to hell, brewed for hours (or days) and then fixed with a big dollop of condensed milk. My wife describes the flavor as burnt tires and old motor oil. But personally, I love it.
