... you have to at least honestly acknowledge it's RECENT history which was the banner under which opponents of civil rights for blacks rallied in my lifetime, in the 1950s and 1960s, and that it's still, in 2018, a banner of self identified racists of all stripes.
... So if I hoist that flag outside my house, I damn well better account for that because someone driving by will have no way to judge my intentions. ...how do I indicate to my black neighbors or others driving by that I mean something else?
...is that for all that I might love about the "old south," it was also an era of state sponsored white supremacy that systematically and at the end of the guns of the state stripped blacks of basic civil rights. So when people fly the flag - heritage, NOT HATE - what heritage are they really talking about?
It's offensive because of the RECENT history and current embrace of the Confederate flag as the banner of white supremacists. It's a problem when you share an affection for the Confederate flag with a guy like Dylan Roof.
The meaning of symbols is a human perception of the abstract, a subjective response. For those who use a symbol to communicate something, to some audience, there is an intended perception and purpose - for those who view it they may or may not see or feel the same perception or see the same intended purpose.
Meanings (and offense) can be intentionally taught or shared, evolve through time, and can vary in context. The battle flag of the Army of Northern Virginia (the St. Andrews Cross) was a soldiers flag, not the confederate national flag - it had one meaning. It was a rallying symbol of the army whose use spread, then carrying a broader meaning, and then its motif was incorporated into various Southern states in their State flags...yet again for other meaningful purposes.
The most prevalent meaning, throughout its history, has been of one of regional southern identity - a pride in one's origins and roots. It grew into, as do most regional flags, an America flag of Americans - just as the flag California Bear Republic and the Republic of Texas became "American" a part of our American flags. It was used in various civic contexts, most of which were that of pride of identity...including its use by American soldiers in all of its wars.
Unfortunately, for the once powerful historic KKK and racial segregationists, it was also a symbol of unity to convey a political message - that pride of the south required a belief in their odious views.
So there are only two choices of contemporary meaning: there are those who want it to have a dominate white supremist meaning (which includes the so-called SJW crowd) or those who wish to keep its broad pride of place meaning...that of an ancestry held in reverence. And given those binary choices, it is not a surprise that those who wish to be their symbol of racial supremacy and those who wish to turn it into an object of anti-racist loathing have mutually complimentary agendas.
For me the choice is easy. If what was sufficiently innocuous to have been an innocent and amusing southern pride motif in, say, the 1980s Dukes of Hazzard (20 years after the civil rights movement) and is then "rediscovered" and resurrected in 2018 to be a newly profane object to spit on, I think their motives to be dishonest - in fact, I think it obvious. These more recent motives have nothing to do with the really serious racism of 75 years ago (that of segregation in education, housing, transportation, etc.), it has to do with the fact that with the major battles won, the most recent two generations have been shaped into crusading 'anti-racists' in search of moral validation - a left culture's self-ginned rage who can only find an American flag to fight over (and to bash southerners with).
I don't fly a confederate flag for two reasons: a) I am not a southerner, although I have lived in a border state and appreciated its people. b) even if I were a southerner, I live among Californians, easily one of the most brain-washed and intolerant people on the planet. There is no reason to invite a brick through my front window or vandalization of my car.
None-the-less, I am not one to allow the political agendas of either white supremist or their bedfellow anti-racist crusaders dictate my meaning, or the current reality. Nor should you.