The flag is there in order that people learn their history just like any other record in history is, and it has been set there in an historical context. This way people can then choose what they see as being wrong with that history or right with the history in their understanding of it and within their learning of it. Just because a radical decides that he wants to take his idled mind and apply it to what ever he wanted to apply it to in his life, and this be it for good or for bad (in this case very bad), doesn't mean that history should be banned or taken down and/or wiped out in order that others can't or shouldn't be allowed to learn about it. It just sets the whole thing up to be repeated again is what it does.
The only thing is this you see, and that is that it will be in a different coat or have a different face the next time around, and the dangers are is that the coat or face won't be recognized until it is learned about possibly in a very bad way over time, and then dealt with as well but in a very late kind of way over time. The problem with doing away with history, is that it opens a new door up that no one is familiar with, and by the time they get familiar with it, then sadly many may die or become abused before it is recognized or found out about just as a new strain of disease or virus is found out about but way to late when it is. How long does it take to roll back those kinds of things, and this because no one new about it prior to or was dis-honest about the symptoms or ways in which they may have contacted the virus or disease? I say leave history alone and let it serve as a reminder always of the good and bad in our societies. Let not history be repeated again due to our young peoples ignorance or highjacking of it for their own rotten murderous devilment they decide to get into in life. Leave the history flying for all to see, but stay pro-active in putting out fires no matter where they may flame up in society.
If don't want history to work against you in life, then don't place yourself in a position where it does work against you in life. Otherwise don't empower the wrong sides of history or give power to those who are on the wrong side of history, but instead show by ones actions just how wrong that history truly was. The Christians are handling the situation in a Godly manor, while all others are using it for every wrong reason that can be imagined now.