When a movement (such as the woke left or far-right) feels it cannot change the wider world (dethrone or enthrone Trump), it turns on those it can control: the people in its party or tribe.
Inside the group, they increase the need for "ideological purity" to weed out interlopers and enforce/institute a hardcore of radicalized ideas, which demand alignment or at least lip-service obedience to remain in the party. (Since we have not made progress, we must go harder: you are either with or against us.)
Examples of pejorative othering are terming: cuckservatives as in-party shaming on the conservative right or naming them a moderate or an ally to stack the progressive left hierarchically.
Any criticality is erased, bad ideas flourish, and extremism distances what should be united.