I'm just trying to piece together what information we have.
It seems kind of odd.
Most wastelanders know the Brotherhood is a techo-religious band of neo-knightly crusaders collecting still-glowing embers of humanity.
A.K.A. over-glorified hoarders.
Ulysses seems to have known nothing about them. Where has he been?
Also the courier knows nothing about the Mojave Wasteland. I realize it's entirely appropriate for him/her to be completely ignorant of factions so it can be explained to the character at the beginning.
But still, you find no evidence of a home and your supposed boss (Nash) doesn't even know you. All the more reason to point to you living somewhere else.. or the divide. The Hometown Hero achievement doesn't help either.
I also understand it's to "give the courier a blank slate" but that's kind of hard when right at the beginning you're told you knew a guy you know nothing about and supposedly you two have a past.
Going back to Ulysses in OWB, he asks "what makes a nation" whereas Elijah asks "what breaks a nation".
Elijah got the Sierra Madre. Ulysses gets a nuke? Seems reversed.
I don't know, what are your thoughts? There seems to be a symbian circle between making and breaking a tribe, greed and redemption, revenge and forgiveness.
Maybe it's nothing. Maybe the courier ate all the gardetto's and left Ulysses with only rye chips. So he plans to blow up whatever tribe you're associated with.

According to the holo-tape they released, Ulysses does know about the Brotherhood. He just disagrees with everything they stand for.

To me, it seemed like he had to ask Christine about them before he knew their philosophy.
Could be reading into it wrong, though.