My impression was that there wasn't a League of Bullies, but that SPHEW might have brought one into existence.
That is, while most of them might not proudly label themselves "bullies", they share a common quality: people who have been embarassed by Granger & co. As it became clear that they would need to band together to redeem themselves, a loose coalition was formed.
So I think of it simply as a bunch of otherwise unaffiliated individuals realizing that they have a common problem and goal, and temporarily banding together to achieve it. Which seems at least more plausible.
Right, they're not the league of bullies; they're the league of innocent people slanderously identified as bullies by SPHEW (the LIPSIBS).
Update: Discussion has moved on to a new thread.
The hiatus is over with today's publication of chapter 73, and the previous thread is approaching the 500-comment threshold, so let's start a new Harry Potter and the Methods of Rationality discussion thread. This is the place to discuss Eliezer Yudkowsky's Harry Potter fanfic and anything related to it.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven. The fanfiction.net author page is the central location for information about updates and links to HPMOR-related goodies, and AdeleneDawner has kept an archive of Author's Notes.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: