There are two problems here. One, people come in such a wide variety of sizes and proportions that the seats will only fit some people, not all. Two, these types of seats are often badly designed with extreme curves and angles which force the user into very poor posture. Typically there is an outward curve in the lumbar or waist area, an inward curve in the shoulder area, and an outward curve in the neck area. Poor posture is more common than it used to be, partly because we sit more than we used to.
Designers make chairs to fit the slumped posture which, of course, only adds to the problem.
And there are fashions in seat design as in everything else. Some of these seats are very uncomfortable or even dangerous to sit on for any length of time, particularly if you have a bad back. Complain to the management and always have a jumper you can fold to make into a pillow to modify the seat. The Campaign for Better Seating would prefer a neutral seat with flat planes so that people can assume their own shape and posture, not the shape of the chair. The stacking chair which is found in lecture halls, village halls, schools and many other places is popular and practical because it stacks.