I don't understand which opportunity the try to find in Local Board in this case. If they leave it once they ranked up, why write and spam there in the first place? I got to, that it is easier and more comfortable to become a part of the community through the language which is your native and with people who have common roots with you. But it is not impossible to fill in even without local support at all. For example, I found out the existence of local Ukrainian and Russian communities after quite long time, when I was already familiar with main rules and customs of the forum.
Because locals always tolerate tiny mistakes. Let's say a new user registered today and copy-pasted some random article in our local thread, in the past days, we were used to asking him to edit it and add the source or delete it. Do you see the tolerance here? Global members would go ahead and report their posts and they would get banned without having a single chance.
We have tolerated many more things in our local thread and that is the reason they were able to abuse every single feature of this forum. Someone has to stand up against them, and I thought it was the perfect time to step up. Luckily it worked and they stopped doing what they were doing for a while.