Let's say for example a player is a male person irl, and irl they like to wear clothing that would normally be considered for women. This fictional person's character is also male and dresses in the same manner.
By removing their glams, which may give them a more conventional appearance (note I say may, because if they have the Shisui gear equipped then that won't happen) you are removing their expression from your view.
You may say "but only I can see it!" but people can take screenshots, and stream. And I can understand someone being upset that their character or even themselves are being misrepresented due to someone else turning off glams and sharing imagery with them in it.
Sure SE could take some measures to prevent screenshots, and maybe even streaming...but mods are also against the ToS and it's super easy to find screenshots that have been enhanced by mods. No matter what SE do, people would find a way to upload imagery of unglammed players.