Hasn't this been the case for at least the last forty of fifty years?
I remember you posted an interview late last year with Erin Pizzey discussing how this was happening with feminism as early as the late 60's and early 70's. Almost anything that starts with good intent and reasonable goals tends to get hijacked by what are by and large ideologue bullies who are crass enough toward those who started it that the movement's originators start leaving one by one. It seems to be one of the plagues on well-intended and self-restrained activism.
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“Love takes off the masks that we fear we cannot live without and know we cannot live within. I use the word "love" here not merely in the personal sense but as a state of being, or a state of grace - not in the infantile American sense of being made happy but in the tough and universal sense of quest and daring and growth.” - James Baldwin