Well, I'm making the assumption that the Brotherhood (excluding Christine and Elijah) haven't chanced upon Big MT yet, or something was pushing them away.
But, having Ulysses mention the Brotherhood in regards to the Divide in a recording about the meteorological station and the scientific catastrophe that occurs to Hopeville, I made another logical assumption that Elijah is Ulysses reference to the Brotherhood. Though, it can also be said that the Brotherhood and the NCR made their path through the Divide for whatever reason.
Who knows until the DLC is released though.
I interpreted it more like this:
Christine and Elijah came to Big MT so focused on their own selfish goals that they didn't realize nor care that they were awakening Big MT and essentially destroying it by "waking it up" This might be paralleling something that the Courier did to the divide, maybe he was so caught up in what he was doing that he didn't even realize he was hurting the divide. Also, I think he compares the Brotherhood to the NCR because the NCR also has it's own selfish goals and they "roll over people"
- Marcus and hurt people without really caring or even realizing their faults.