It’s funny how they mistake our resolve for incivility, and their own incivility for resolve.
That's a very nice turn of phrase, and I believe the reason why it is true has to do with the Utopian nature of Progressivism. Opposition to any element of their belief system is taken not as the result of reasoned, articulated thought, but as evidence of wrongness at least, and evil intent at worst.
Conversely, Progressives become so confident in their own rectitude that they are almost uniformly non-reflective and obdurate.