edit: I missed a bit of the sentence in my updated translation, but the part I take issue with most is the translation of 黒人たち to "blacks" which is racist, and should be corrected to say "Black people"
It's possible that the sentence is translated the English to the Japanese. Sentences on Tatoeba (if you click the link to the bottom right of the sentence, it shows it came from Tatoeba) can be submitted by anyone, from any language to any other.
Jisho just takes pairs of English and Japanese sentences and uses them here automatically. I imagine that it's possible for the creator of Jisho to completely remove this pair, but only the person who wrote a sentence on Tatoeba can edit it. That would be the place to reach out to the person who wrote it.
Thanks for pointing this out. This could potentially be fixed on Tatoeba by editing the offending sentence. But it's owned by someone who seems to have email notifications turned off, and I couldn't see a way to comment anymore.
So I created a new sentence with your suggest translation, and hooked it up so Jisho and others who use the Tatoeba Japanese index system will see that one.
It should show up on Jisho with next week's data import.
Racism in this translation
The translation says "blacks could win their fight" but referring to Black people in this way is degrading and dehumanizing. It should translate to "He believed that Black people could win their fight for equality."