According to Robowars, it really means BIG Ass Mother Fuckers.
No clue why they each have a big ass though.
. As in, they have big asses?"~Spoony
"Why do they have nicknames?"
"You know what the group is called: B.A.M.F."
"Big Ass Mother Fuckers"
"Sorta like, get to it and go get FUCKED like in (Viet)Nam"~ Two guys in Robowars.