as a rule, so should a good photo.
There is literally no rule that says this.
It's a stylistic choice.
You don't like it, that's fine. Others do. But there is no "rule".
Yes there literally is a rule.
There are rules in photography as in most things. For example: the subject in a photo should be in focus. All rules have exceptions and we've all seen out of focus photos that work, but exceptions don't negate the rule or make the rule less important. In the overwhelming majority of cases a photo with an out of focus subject is recognized as a mistake because it breaks the rule.
[Good tonality in a photo requires (among other things) reaching a black point] is a venerable and fundamental rule with the historic weight of well over 100 years of accepted practice. My teachers taught me that rule 40 years ago. Remember learning the Zone System and all those paper DMAX tests we had to run to determine minimum exposure to black? We did that to make sure we were following the rule -- it's a well acknowledged rule and for good reason.
It's easy to find references to this rule:
"What makes a compelling photograph? Well, there are quite a number of things and one of them is 'Black point'.... Photographs look better if they utilize most if not all of the inherent dynamic range of the medium, be that paper, a computer monitor or some other electronic medium. This is to say that the image has deep shadows, brilliant highlights and the full range of tonalities in between."
-- Ralp Nordstrom
"Ansel Adams wrote extensively about the importance of blacks in a print in his classic book, The Print. While there’s only one true black tone in a print, there are usually many spots of black throughout the image, and this is where the term 'blacks' comes from. Without blacks in a print, it will never have the life and depth it needs, and with color images, the color either."
-- Rob Sheppard
"Most images look best when they utilize the full range dark to light which can be displayed on your screen or in a print. This means that it is often best to perform levels such that the histogram extends all the way from black (0) to white (255). Images which do not extend to fill the entire tonal range often look washed out and can lack impact."
-- Sean McHugh
Joe