If your flag causes you to sin against your fellow man, you should burn it. This may not be found in the original Biblical text, but I believe it captures the spirit of the advice. It is just all a variation of “love your neighbor as yourself.”
When my children were little, sometimes one of them would come to me complaining about a sibling getting into his stuff. I would tell him that I would defend his property rights (in terms he understood), but I often saw a need to address his own attitude toward the other person. I desired both parties to come away from the incident understanding that what was really at stake was the relationship. 
A flag is ostensibly a symbol about relationships, but the trouble is that a flag rarely means the same thing to everyone. That gets to be even more complicated when some of the people begin to think of the flag as part of their individual identities. Some people claim a flag is a symbol of freedom, but then their identities are bruised by those who see a flag as a symbol of oppression.
The people who think of a flag as a symbol of freedom have a problem if they think they have a right to tell others how they must think and act toward such a flag. They are assigning more value to an inanimate object than the real ideal. They cannot logically claim the importance of the symbol of freedom while persecuting those who use freedom differently than they do. Assuming no violence has been perpetrated against their person or property, they have no legitimate complaint.
There is freedom inherent in the injunction to “love your neighbor as yourself.” Each person is free not only to love, but to choose how to love, for no man can truly force the will of another. Compliance of outward conduct may be coerced, but true love cannot be.
Neither should a person attempt to force respect, in word or action, if they value freedom for themselves. If they do not also value freedom for others, they degrade freedom for all. Though they may seem more free compared to others, where there is not mutual freedom, there is not true freedom for anyone.
Unfortunately, there is currently a parallel between flags and gang colors. If someone doesn’t show subservience to the gang colors when in a certain territory, they risk much. Why? Because the colors are used to exert authority and demand allegiance, all under the guise of maintaining order.
Surely most of us can rise above this. If some people want to try to use a flag to represent freedom, that is fine, but they should be willing to peacefully and humbly make a case for it. If this turns into a devotion to the symbol that surpasses their love for their fellow man, I say they should burn their flag and try again.
