I actually figured out why Blacks have gone through so many names for themselves.
Every time one of those names becomes too associated with themselves and their race, they want to change it to something new, a name that has not been "tainted" by association (in their own view!)
This is not a question of White racism. This is a question of black self-hatred. They are the ones demanding a new designation every few years. As soon as the previous one is firmly established in the language, and in the public's mind with themselves, they want to change it.
It's as though THEY feel that they are inferior, and any word that too closely is associated with them comes to be, in their minds, an insulting epithet.
Hence "niqqer" (which was just a southern, lazy pronunciation of "Negro", like "nigra"), was changed to "colored", which was changed to "Negro", which was changed to "Afro-American", which was changed to "black", which was changed to "African-American"...
Where do they go next?
Until they become secure and happy with, and actually proud of, themselves as a people and a race, they will continue down this road. And there is nothing anyone else can do to help them. It's internal.
By contrast, White People have been called White since the first time they ran into someone who wasn't. And being secure and comfortable with our race and culture—generally speaking, we've never felt the need to "upgrade" it.
At least, that's how it seems to me.