I'm not sure what's the bigger culprit of thin bitter coffee. The cans of cheap grounds at the grocery store or the electric drip brewers that fill the carafe far too quickly and don't give the grounds time to steep.
Grew up with parents that used Bunn machines that would make a solid stream of lightly colored water flow through that was extremely bitter. I have a cheap Black and Decker that takes much longer to brew and is much smoother and more flavorful. Always used creamer and sugar with those.
Now drinking my first cup from a french press steeped for 6 minutes. Thick almost oily black coffee with chocolate notes and no bitterness at all.
Somepeople say, its water temperature that pays into a bitter cup..