It was never about that, most of us were only there for the chuubas and didn't really bother anyone else, but that meant that the vtuber thread was a bit like a foreign enclave in the farms, we have our own lingo and obscure references that only chuuba fans understand and the thread was one of the largest and fastest moving in the whole site. It also isn't a thread exclusively set on mocking vtubers, but rather one set on neutral discussion and in many times borderline simping, that pisses off people who view the whole fandom as degenerates.
Why should degenerates have a safe place in a site literally dedicated to mocking said rejects of society? The anger and disgust a lot of people feel towards the motherland thread is quite understandable when you realize that in the eyes of the wider internet, vtubing is comparable to other weeb trash at best and on the same level as furries at worst.