The usual meaning of “anti” is against. Therefore, Anti-Nephi- Lehi (v. 17) suggests the people were against Nephi and Lehi. However, Dr. Hugh Nibley “has found a possible Semitic and a common Indo-European root for the word anti that means ‘in the face of,’ or ‘facing’ as one of facing a mirror, and by extension, ‘one who opposes’ or ‘one who imitates.’ A possible suggested meaning of the term Anti-Nephi-Lehi might then be one who seeks to imitate or reflect in his life the teachings or conduct of Nephi and Lehi.”
The curse that “did no more follow them” (v. 18) was their being “cut off from the presence of the Lord” (2 Nephi 25:20). The dark skin was the mark of the curse, not the curse.