To be fair, how I (and others) calibrate a TV isn't always the best fit for games. The standards are aimed at film content.
Game content, however, has no real standard so it's impossible to properly calibrate a TV to work with it. I always like to do one "picture mode" to ISF specification, copy it, and then modify a second mode to produce an image more pleasing for games. Of course, I still keep sharpness disabled along with anything else "dynamic" as that ruins the image.
The problem here is that some people actually think these artificial enhancements look great. Why is that a problem? If people like the look of something, why not use it? The issue arises when the type of content switches. Those dynamic settings can look acceptable with certain types of imagery but, switch to something else, and suddenly the picture looks terrible. A bright outdoor scene looks vibrant and sharp, for instance, but a dark underground, dimly lit area will be completely missing detail while colors (such as skin tones) are destroyed often appearing more red/orange. Basically, those enhancements are poorly suited for ALL content.
Calibration is designed to provide an even, accurate experience across all range of content which matches what you were intended to see. As I said, it doesn't really apply to games as much due to lack of standards, but the results are still similar with some scenes being ruined by these enhancements.