As regressive leftist ideologies have roots that go as far back a century to the neo-Marxist concept of critical theory, I was wondering about early examples of regressive leftist bullshit.
The earliest manifestation of the early regressive left I can think of was with late 80's-90's third wave feminism, with notable victims in the games industry including the Leisure Suit Larry series and Duke Nukem 3D, which in the case of Duke 3D likely cost 3DRealms sales.
Some other examples include the Resident Evil 5 black enemy drama, the false claims of ableism against Derpy Hooves, the Penny Arcade dickwolves drama, early ComicsGate, and the takeover and subsequent destruction of the atheist community by the Regressive Left.
Can you suggest any others I did not cover?
The Loony Left, a 60 Minutes segment from 1987 about leftist indoctrination in elementary school education in England.
A 1996 lecture/interview with Peter Theil on the negative effects of multi-culturalism and diversity
There an interesting summary of a book about Western liberalism written in 1964 that suggests that the basic thought processes that have resulted in "regressive leftist bullshit" are basically unchanged since at least that time and certainly earlier (because they would have had to have been unchanged long enough for the generalizations to have been made in 1964), and looking at it that way you could make the argument that even things like the Civil Rights Act were a sort of "regressive leftist bullshit".
It is believed that the current regressive left does have origins in civil rights era extremism.
I just like bringing it up because oftentimes when I ask people "when do you think the left stopped being 'liberal'" they answer "about 2014".
No the left integrated schools in a very non-"liberal" way as well: via Federal regulation and courts, and ultimately at gunpoint using the National Guard and military.
Argue all you want whether or not it was a justified use of illiberal coercion against an unwilling local population, but that's exactly what it was.