Gerrymandering by latino and black caucus

http://www.npr.org/2011/10/31/141457122/chicago-leaders-spar-over-redistricting

Lobbyists that want to redraw voting district lines so that minorities get more representation....

The city's Latino population is now at nearly 30 percent. Alderman Danny Solis, who heads the City Council's Latino Caucus, says the ward map the Black Caucus proposed is simply a starting point. It would drop one majority black ward and create two more majority Latino wards.

"The numbers we have now are not enough. The figure speaks for themselves. We are in need of more Hispanic wards in the city of Chicago," Solis says.

basing the choice of their representative not on actual issues but the color of their skin.
You're just making that up. The two are not mutually exclusive. In fact a latino or black representative will probably be the only candidate that actually shares their views on most issues. For example, they tend to be very conservative on specific social issues like gay marriage but liberal on most other issues. A white politician who is lenient on immigration but against gay marriage would be practically non-existent.