A Bunnybrick is a non-complimentary term you give someone who is massive, muscular, and appears threatening in every way - except that in real life they are actually quite timid, self-conscious, and sometimes act childish. Usually they are hired by other gangsters because they are easy to manipulate, can do strong jobs, and work for little pay or return.
"Are we still on for that bank jobtomorrow evening ?"
"Yeah. Mac, our local bunnybrick will take care of the guards."
Term used by teenage boys when they desperately want to have sex with a very hot looking girl....they just want 5 minutes to put it in, wiggle, and pray to God that they can cum.
The real reason that he defected to the British side --- tubby prune-faced ol' "Key-and-lightning" Franklin had been overly friendly with him (and of course we know for sure that he didn't used petroleum jelly, either, since said lubricant wasn't even discovered until 1859!), and back then sexual-harassment lawsuits were virtually unheard of.
We all know that Mr. Franklin was a strong supporter of gay-friendly society, but after the Bennydicked Arnold affair, one has to seriously wonder if the enigmatic "Fart Proudly" essay-writer's orientation was itself at least partially "on the fence".