Why would the B1G or SEC feel any animosity toward the PAC, B12, ACC? There's no rivalry there. There's no competition.
As a fan of a B12 school watching all of this unfold over the past decade+, I never felt like the SEC or B1G felt animosity toward the B12. My perception is, they don't feel ANYTHING at all. It's all just business, exclusive of emotion. Those other 3 conferences are viewed by the B1G and SEC as being solely for consumption.
But I most definitely perceive a rivalry between the SEC and B1G. Perhaps that will stabilize and go away, once the TX/OU and UCLA/USC moves are complete and the dust settles a little bit.