The current polarization has been caused by political correctness and the inevitable push-back against expansive redefinition of previously well understood term

The current polarization has been caused by political correctness and the inevitable push-back against expansive redefinition of previously well understood terms such as: racism, sexism, and xenophobia. Take immigration, people who wish to discuss immigration often end up getting called racist or xenophobic, and the response is then: "f*ck you, I'm not a racist". Thus you have polarized the community.