You are correct. Southerners called this "Squatter Sovereignty" and it made them fighting mad. For that reason you can pick up a Southern newspaper from 1860 and read lots about Douglas but almost nothing about Lincoln. The Charleston platform endorsed States Rights as opposed to "Squatter Sovereignty". Some Southern news editors supported Douglas, believing he would be more likely to get support from both North and South, while others favored Bell and Everett.
We know how this turned out.