In the DSS Calculator, entry of population size of 1000 AND also a sample size of 1000 produces a 0% sampling error, because the entire population went into that sample, so any second sample of 1000 cannot possibly vary from the first one.
That's true for all finite population and sample sizes, such as the 2004 presidential election voter turnout of about 122,000,000.
Content addressing an explosive topic is not itself grounds for sensing "ugly" in a poll.
I recommend studying the legitimate polls to see how two or three of them address such hot-button topics as abortion or gun control. Enough Already with Random Digit Dialing: A Proposal to Use Registration-Based Sampling to Improve Pre-Election Polling, May 5, 2002.
A self-selected sample that is randomly selected from a population has no specification of sampling error--as the term is meaningless in that context.