It's one thing to say that the South exploited a people and a system to further it's political end. It's another thing to frame it as a necessity. Doing so absolves the actors of fully acknowledging their free will, and it disregards not only the sociopolitical context of slavery (as if it were only a political or economical institution), but it doesn't speak to the motivation of slavery before the war.
I found the reference offensive, insensitive, and historically inaccurate and incomplete, and I am fine if I stand on that island by myself. Or, in this case, with McClurek - thank you McClurek. I find it odd, though, that there are some people who find the core issue too irrelevant to be broached, and yet reacting to someone who is interested in the conversation is worth their time and energy. If you really don't care, then why reply at all? If you care and just happen to disagree, why reply with sarcasm as if doing so strengthens your position? Why not just move on to a different discussion that is more worthy of your time?
I get that everyone isn't going care or agree, but if one really doesn't care or agree, why respond with such vehemence? if it's a non-issue for you, then the fact that I care should also be a non-issue, especially since I'm not asking anything of you - not your support or agreement, not one thing.