I mean no, they’re not wrong it is about states rights in relation to owning people, it can be both and also a interstate b trade dispute which is why they wanted the federal government to step in.
Essentially “we’re losing in trade to x because slaves are running to x so they can be free” and then they asked the federal government to step in and say slaves that escaped to the States should still be seen as property and not granted freedom. The federal government took no stance and are largely at fault by inactivity.