I mean, they took a sample of the sub, and that is what they found (see their notes on data collection process done via Reddit Chat)
Regardless, I agree with you, the groupthink is the issue here - I do think it is telling though, that it is a groupthink (allegedly) skewed by the white male perspective. Which I think is also an issue, lack of representation in such echo chambers. But you’re right - two separate issues that happened to be intertwined here. Anti-racist echo chambers are still echo chambers.
