I've tried answering that question for a long time. Since the Kavanaugh hearings. The voters' mindset I get, they just believed the lie they were told. But the people in that picture know they are lying. Why?
I think it's because this has become the religion of the progressives. The dogma of power hierarchies and systemic oppression (that old friend, Marx), the original sin of slavery, and the requirement that you proclaim your faith despite what your lying eyes see. There are hymns (SJW vocabulary like antiracism, unconscious bias, systemic racism, white rage, whiteness, privilege), prophets and priests (Ta- Nehisi Coates, Ibram Kendi, Robin DiAngelo), tithing (political campaign donations), confession... The list goes on. And just how the Catholic Church reacted horribly to the enlightenment, and nearly every scientific discovery that even remotely challenged the church's narrative, the progressives *hate* anything that threatens the "perfect word" of their God: the evil and racist nature of the American system, in which there is no justice for the oppressed.
That's why they hated Rittenhouse so much, and it's especially why they hated the Darren Wilson case so much, and why they completely ignored the Eric DeValkenaere case. The first case attacks the purity of the cause. If Kyle was justified, then that night in Kenosha really was a riot, not "mostly peaceful protesting" for black rights. The second case reminds us that cops are more likely to be killed by black people than black people are likely to be killed by cops. There are very few actual cases of cops killing unarmed black people on which to build this vision of wide-spread sport-hunting by the police of minorities; Michael Brown was a martyr turned villain. And the last case proves that there is infact justice for minorities in America.
Once you accept that the people driving the progressive movement know the narrative they are promoting is false, it becomes a lot easier to predict the behavior. The things you focus on and ignore when protecting a lie are different than when protecting the truth. Gaslighting, straw men, ad hominem attacks, appeals to authority, false equivalency... All tactics to distract from a weak position.
They have committed to the fundamental notion that America is broken and needs to be radically changed. Build back better, right? They want the "new America" but lack the justification, considering the wild success of the American experiment for *all* citizens. So they are just making it up.
Now that they are committed, and their power is tied to that cause, what choice do they have?