I think Starbucks tries to cater to people who like the flavours in black coffee, but enjoy drinking their coffee with dairy. My theory is that it's 'roasted to pair with dairy' and if you drink starbucks coffee black, cold brew, or espresso without dairy, you're missing half of the 'starbucks' flavour.

I prefer my coffee black, so that makes starbucks worse than most fast-food coffees flavour-wise (though I still enjoy Starbucks locations and amenities better :D)