I don't think there is a right word, but I recognize this behavior from history books. During the French Revolution the participants were similarly convinced they are doing the right thing, and they reinforced each other's views. The crowd had a feeling of a common cause and their combined strength. They believed that by beheading Marie Antoinette they are doing everybody a favor. Similarly during the Russian Revolution, the masses believed they are fighting for a great cause, some even died for it. But the revolutions are usually eating its children, and similarly now the revolutionary feminists of yesterday are being eaten by even more progressive trans activists. As Ricky Gervais said, the same will happen to the latter one day. [0]

[0] https://www.independent.co.uk/arts-entertainment/tv/news/ric...