system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What's wrong with the word 'negro'? How is 'black' politically more correct than 'negro'?

From wikipedia: The word “Negro” is used in the English-speaking world to refer to a person of black ancestry or appearance, whether of African descent or not.

I am from India, where 'Negro' is still a well accepted term for blacks, so I am curious what happened elsewhere?
gpt
Apparently words that have a neutral definition can become slurs if they are constantly used to describe someone we don't like.  Negro, just as a word outside of any context, is completly neutral; it's the Spanish word for black.  However, because it was previously used to name people that we oppresed, the word is now bad.  Just like Chinaman or Jap.  Chinaman is bad but Englishman is good, and Jap is bad but Brit is good.  These words are bad because at some point in time, they were used negatively.  If there was a big war, and the word "person" was used to describe the enemy in propaganda, you would not be allowed to call anyone a "person" afterwards.