To zoom out, there’s a HUGE percentage of the US who uses “common sense” as a catch-all excuse to end all discussion.

In the debates I watch, they typically don’t have the mental capacity to steel man the opposition’s position so they can’t comprehend that someone else has a different intuition / “common sense” than them.

Beyond that, “common sense” has become a dog whistle to both virtual signal / vice signal to like-minded in groups and to deride outgroups. In a way, using that phrase is a way to dehumanize the person they are talking to.