“and a duty to never cheat, steal from, or defraud a Brother Mason.”
Simply reading this implies that it is conversely OK to “cheat, steal from, or defraud” others.
I would assume that this is not the intent, but why is the quote worded in this manner?
Since I don't believe you asked this as one of the "haters", I'd like to answer.
The wording was actually mine, and I paraphrased it badly. We do, however, promise not to cheat one another because we require a special mutual trust.
I can be completely trustworthy to others, but that doesn't mean that I should completely trust them. The mutual trust between Masons is one of the things that makes the fraternity special to many of us. I have no worries about a Brother Mason hitting on my wife. I wouldn't hesitate to hand a Brother a sizable amount of cash to donate for me when "the hat is passed" in my absence. That level of trust is rare throughout the general public.
We are actually self-policing... in that if a Brother knows you to be cheating others or acting in an immoral manner, it is his duty to counsel you on it. If you do not amend the behavior, it is then his duty to bring the situation to the attention of the Lodge.
I hope this clears up my earlier poor wording that may have led to the understanding that it is OK to cheat non-Masons.
Maybe an excerpt from one of the lectures will help clear it up. It is speaking about morality and a Mason's duty to his fellow man:
"...realizing that not only those here in the Lodge, but all men are your brothers".