To be perfectly blunt, these people don't hate your coffee, Starbucks. They hate YOU.
Oh Starbucks, why must you bow to peer pressure? Why must you try to be all things to all people? First you started serving what are basically milkshakes, in order to capture the "non coffee-drinking fatass" crowd. (P.S. I myself am a fatass, so I'm allowed to use that word.) And now you are trying to cater to people who think your coffee is "too strong."
You know what we call people who think your coffee is "too strong"? Chumps. Punters. Whiners. Babies. There are a lot of terms you could use. But I assure you that one thing we would never call them is "coffee lovers."
For people who think Starbucks coffee is too strong, or who whine about "the burnt taste" (and if you use the word "Charbucks" in my presence I will give you such a smack) there is a whole wide world of lousy, weak coffee. Sappy pale tea-colored coffee-flavored beverages are everywhere, from the gas station to the doughnut shop to the grocery store aisles.
Here's the thing. A certain sub-set of people will always feel the need to hate on whatever is popular. Those people claim they hate Starbucks because the coffee is too dark. Because what else are you going to complain about? "The stores are too conveniently located"? "The locally sourced baked goods are too delicious"? "The price is too reasonable, given the market value of a latte"?
There's no point putting out a lighter roast, because it won't address the real issue. To be perfectly blunt, these people don't hate your coffee, Starbucks. They hate YOU.
They hate what they feel you represent. It's ridiculous to conflate a coffee company with a worldview or an ethos, but that is what they do. (It's every bit as silly and deluded as your fans who do the same thing, but in the opposite direction.) They hate something that you can't change: they hate your ubiquity and your success. Some people also hate what they feel is your effete snobbery, with the way you cater to them book readin' yuppie folks.
No company can be everything to everybody. And if you try, you'll just overextend yourself, and then where will you be? Trying to return a gazillion countertop Egg McStarbucks sandwich ovens back to the manufacturer, that's where.
Oh dearest Starbucks. To coin a phrase, don't go changin' to try and please me… I'll take you just the way you are.