Another one of "my" headcannons: Changelings do not have as much individualism as many other blogs describe them to have. They may have different personalities, but usually don't try to differ their appearance because of it. Imagine a teenagers need to be accepted into their clique, then have that feeling multiplied by >1'000 and you have a changeling's need to be one with their hive. This is why leaving a hive is considered one of the worst crimes, punishable by death.
I can see this happening in some groups.