Unity is an anomaly. Polarization is normal. Skepticism about liberal democracy is also normal. And the appeal of authoritarianism is eternal.
For some people, loud advocacy of Trump helps to cover up the deep doubt and even shame they feel about their support for Trump. It’s not enough to express tepid approval of a president who is corrupting the White House and destroying America’s alliances. You have to shout if you want to convince yourself as well as others. You have to exaggerate your feelings if you are to make them believable.