Have you ever been uncomfortable because the train seat is too tight? Feeling uncomfortable at an exhibition where spaces are tight? Have you ever had to ask for a belt extension on an airplane? Or had to resort to online shopping because your size is not found in the store?
If you have never experienced any of these sensations or, while reading them, you thought that "it would be enough to go on a diet" it is because the fatophobic mentality is internalized in most of us: no one and no one is immune to it.
If these things have happened to you, it is because your body does not reflect the predominant lines and is therefore invisible to the design. The bad news is that it is not a question of invisibility due to naivety but to a moral judgment on fat and a precise economic choice. Because, coincidentally, the standard sizes allow for mass production and maximum optimization of space.