I'm not in favor of keeping all of the old Confederate monuments, or flying Confederate flags on government buildings, and I'm generally disgusted by many of the arguments in their favor.
But in response to this:
> There might be people out there who have this as an agenda, but I doubt that many people subscribe.
just like most of the pro-Confederate monument arguments you ever hear are apologies for slavery or denial of its role in their history, most of the arguments against whatever offensive thing people want removed are really just about how it makes them feel, which is hardly and adult attitude toward how we should remember history.
And I don't really agree with all of your second point. The U.S. has a unique genesis but those other countries are forged out of unique groups of people, and Americans have disagreed about the "governing principles," and "set of values" from the beginning. And are we really less "one people" than countries like Russia? If you really buy the arguments you made, the U.S. is the only country where someone who doesn't have ancient roots there can ever truly belong.