glasses can absolutely make someone ugly if they are not matching to the face. Also, It's part of the bigger picture mixed with the socio-cultural situation. If glasses are attributed to commoners in this setting, they will seem unattractive.
Same with a tan irl - it's attractive in cities because it signals that person is well off enough to go on vacations, and tan is unattractive in rural places, where it's attributed to working on the farm.
Manga is still rather meh tho, I would respect the redhead boy who seems to be a lead more if he had not simped for MC when she was a shallow idiot.