When did you get here, anon? Cirno has been sort of a part of /bant/ since the day it was founded. Here's proofs: >>1018
and for the most part people railing against her did so because of what some viewed to be mod favorism since her posters weren't getting banned for avatarfagging while the posters of similar waifus such as Kotori, Magumin, and most notably Kagari were, which is what led to the Kagari incident of July, or in the case of Chicanon and KNS because she resembled an anime character and those people did not like anime posts on /bant/.
Slowjaks came along during the tail end of October around the same time their threads stopped existing on /lit/: they didn't even exist on /bant/ before then and the only poster identifiable from /bant/ before their presence was the Canadian that made the Wosak edit who previously backed Kagari. Any /lit/ regular prior to them giving the boot would recognize them as "brainlet wojaks" and they needed somewhere to spread their ironic shitposting. /bant/ gets the most recognition due to their concentrated spamwave, but the spam was occurring on multiple boards including /v/, /pol/ (who hadn't encountered them in any large numbers beforehand and was making threads about it) and /his/. Unlike the above groups, they never stated any reason they opposed Cirno beyond ">cirno is /bant/ culture" and wanted to displace her because by removing the people that associated with her, they either rightfully or wrongfully thought they'd take out the core of old /bant/.
They did similar shit to /his/, mocking regular threads and spamming the board until they were removed, which is proof enough that it was a conditional attack based on the type of content the board was producing as opposed to any misgivings on the actual character.>>4520897
I distinctly remember the post reduction coming around before the Slowjaks, but I might be getting it confused with the image repost cooldown that was used to curb banana posting.