I calibrate using this but I don't think this is a calibration issue. If ones monitor is too dark, one would over compensate for the highs and the final image could be viewed as being too bright with no dark tones while an image that is created on a monitor that is too bright might be seemingly too dark because the creator over compensated for the lows.

This is more about tonal range and lighting [like orbital suggests]. Of the images I would define as having very little tonal range [or dynamic range] they are the ones that are 'too dark'. It's not so much that they are 'too dark’ - more to the point - it's that they have no tonal range or key lights. They are seemingly stuck between the white point and black point making them very flat [erring closer to the black end]