Rikyrah at Jack and Jill Politics points to a Gallup poll titled "Whites May Exaggerate Black-Hispanic Tensions" which may explain why the conventional wisdom about black-Latino tensions affecting Obama was so completely wrong.
The generally positive review of black-Hispanic relations in Gallup polling among members of the two leading U.S. minority groups contrasts with considerable media speculation about the impact of Hispanic animosity toward blacks in this year's primary elections.[...]
While black-Hispanic animosity may exist and could even have been a factor in some state caucuses or primaries, the Gallup data indicates it is not overwhelmingly obvious to members of either group. Whites are much more likely to believe the two are in conflict.
But why was pundit class was so quick to wrongly assume the state of black-brown relations was poor? The poll suggests this misconception widely held among white folks, not just TV talking heads. Of course, that may be because people were listening to said talking heads, who were all inferring that Latinos just don't like black people based on their enthusiasm for Hillary Clinton.
Part of it probably has to do with a genuine lack of familiarity about the diversity of Latinos, whose cultural and ethnic differences are often obscured by the fact that they share a common language. The perception that blacks and Latinos are often competing for the same jobs probably also contributes, but the idea that said competition translates directly into heated animosity is obviously a stereotype. It's also likely that in a country where people are often more concerned with being perceived as racist than actually being racist, it's easy to project racial one's racial anxieties onto someone else.