Do you think Warren as VP will alienate AA voters?

[frazzled]

40. We're comparing her support to Harris's

So we have to go back to the primaries

Joe Biden leads with black voters, and Elizabeth Warren and Bernie Sanders are making better inroads with younger ones than Kamala Harris and Cory Booker. In interviews, voters rejected the idea that racial representation equated to change.

... In the latest national polls, Senators Elizabeth Warren of Massachusetts and Bernie Sanders of Vermont, the two progressive standard bearers in the Democratic primary, are Mr. Biden’s closest rivals in terms of black support — not Ms. Harris, of California, or Senator Cory Booker of New Jersey.

https://www.nytimes.com/2019/11/25/us/politics/2020-election-black-voters.html

Your results from Massachusetts are pretty irrelevant in this discussion. Harris dropped out of the race on December 3, 2019 (A bit more than a week after the above article was published). The Massachusetts primary didn’t take place until March 3, 2020, three months later. And using Massachusetts results as a yardstick for African American support would not be very indicative in the first place: the black population there is only 8.8%, well below the national average.

Warren, for better or worse, has more support from younger, more progressive black voters.