This thread was deleted from 8chan less than ten minutes after it was created - too fast for even any archives to be created - and the poster was instantly condemned as a criminal for carrying out this criminal act. That is an extremely impressive response, especially when compared to anything from Big Tech.
I haven't quite figured out the timelines in the court documents but it's clear that the authorities were in the subsequent discussions and took the screenshots themselves because of the (You) markers next to their comments.