As they say in 12 Step programs: “Denial is not a river in Eqypt”. 
Using non-dual terms like “formless”, “it’s all one”, “beyond good & evil (Guna-tita)”, etc. to justify what most societies would regard as bad behavior is just disingenuous and/or deluded . If your consciousness is permanently fixed in that realm, you might be able to “get away” with actions that might be condemned in most societies; but I think that even your so-called “perfect masters” (if any actually exist) need to adhere to these moral rules, if only to set a good example for their “non-perfect” devotees and students still stuck in the the world of duality. I’ve seen too many devotees justify and then emulate their Guru’s bad behavior, i.e., abuse of power, violence, lying, denial, theft, spying and harassment, etc. in the name of their guru or spiritual/religious group. This is true cultism.

I think it’s best to judge ourselves and others by the ethics and morality we learned in school, and taught by all great religions and philosophies. It can be summed up in what is commonly referred to as the Golden Rule (from the Christian Bible), but exists in all world religions. 
Here’s one from Hindu scripture: 
“One should never do that to another which one regards as injurious to one’s own self. This, in brief, is the rule of Dharma. Other behavior is due to selfish desires.”
—Brihaspati, Mahabharata (Anusasana Parva, Section CXIII, Verse 8)
Or from Judaism:
“That which is hateful to you, do not do to your fellow. That is the whole Torah [Wisdom]; the rest is the explanation; go and learn.” ~ Rabbi Hillel the Elder
—Talmud, Shabbat 31a, the “Great Principle”
More here: http://en.wikipedia.org/wiki/The_Golden_Rule