Question: A New York Times Service article on a poll concerned with the opinions of Hispanics included this paragraph:

The poll was conducted by telephone from July 3 to 27 with 3,092 adults nationwide, 1074 of whom describes themselves as Hispanics. It has a margin of sampling error of plus or minus three percentage points for the entire poll and plus or minus four percentage point for Hispanics. Sample size of most Hispanics nationalities lie Cubans or Dominicans was too small to break out the results separately.

Why is the margin of sampling error” larger for Hispanics than for all 3092 respondents? Why would a very small sample size prevent a responsible news organization from breaking out results for Cubans separately?