Why do native English speakers make fun of the accents of dark-skinned people?

I am dark skinned and English is not my first language. I still make mistakes and speak with an accent. I am constantly bullied by native English speakers. They treat white-skinned people with respect, but they do not show the courtesy to respect dark-skinned people like me.

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2 mo
I am not black. I am dark-skinned.
Why do native English speakers make fun of the accents of dark-skinned people?
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