The social split in the community complicates matters considerably. Questions which require complicating the electoral system don't come up in a homogenous population. And it probably wouldn't come up, or be as striking, if the two populations lived in separate districts; then the districts would get ethnically-representative representatives. I can only assume that the populations are finely intermingled, thus there's no district where the near-half Latino population can get any represenation at all. The social dichotomy leads to a tyranny of the (small) majority.

The fact that this sort of situation only arises when there's diversity in a community explains the partisan dichotomy of opinion in reaction. It's a matter of how much you value you place on ensuring that a maximum number of people have political representation. That's a pretty reliable political litmus test to distinguish conservative from liberal.