Various reasons for this have been posted:
1. Trump is an entertaining guy who appeals to a broad cross-section of voters.
2. "What have you got to lose?"
3. Variation of #2: Obama has been an unmitigated disaster for black Americans.
4. No self-respecting man of any race or ethnicity would ever vote for a screeching banshee like Hillary Clinton.
The GOPe’s “Big Tent” that they don’t want now because it goes against their donor’s interests. LOL
5. The pure Marxism of Black Lives Matter