All too often these days, when the average person talks about principles, what they’re really talking about are their personal commodities—exchangeable and available only to the select. Oh sure, this merchandise is labeled as “principles” but the definition of the word has become mutable--Truth become the Lie.
Thus does the Golden Rule, “do unto others as you would have them do unto you,” become “do unto others as your preconceived notions would have you believe that others will do unto you.” Or does the Rule come with a codicil: “do unto others as you would have them do unto you—but only if you believe that others follow this rule.”
Of course the Golden Rule has constraints—like all rules which exist in the realm of human imperfection. It cannot and, sometimes, should not be followed 100% of the time. There are exceptions to every single rule under the sun. But if the Rule is to be thrown out of the window every single time it gets a little difficult to follow it, then why bother to even pretend to follow it? (And, please people, on those occasions when you're not living up to your principles, you could at least acknowledge that you're falling short instead of childishly pointing at the other guy and say "well he's not following the Rule either.")
If your “principles” are always for sale, then call them something else, because, in spite of the Theory of Relative Definitions for Words Which Have Fixed Meanings in the Real World, they are not principles.
Call them The Family Jewels and sell them on eBay. You might fetch a high price for them.