I'm with Mr. Wonderful. The actions taken were the result of the SEC and Texas A&M making movements. This caused the ACC and the B12 to evaluate their positions and take steps to prevent their conferences from collapsing.
The ACC was in a weak position from the standpoint of a "weak media" contract. It wasn't that the contract was bad, it was the idea that members may have been envious of other contracts, and may have been expressing they could act on that envy. The invite of Cuse and Pitt allowed for the ACC to improve the contract with the hope it keeps its members satisfied. Whether this satisfaction and stability is short or long term still remains to be seen.
The B12 was and is still in survival mode. They were losing members as fast as the BE and had to take action if they were to survive.
The game of conference survival is no different than survival in real life. The medium fish go after smaller, weaker fish, but the biggest and best of the smaller fish. The ACC and the B12 have no power to attack the SEC, B!G or PAC. So they turned their attention on the best little guy - the BE. This is no different than the BE not being able to attack the SEC, B!G, PAC, ACC or B12 at this moment, so they go after the MWC and CUSA.
I seriously doubt these other conferences primary reason for action was to eliminate the BE but to ensure their own survival. The secondary reason, the elimination of a competitor could help them in the long run, but that isn't a certainty.