I heard what you said, but I just don't give a shit. "Your concern is noted" is the perfect phrase for casually dismissing an opinion you disagree with. It demonstrates a lack of concern by displaying an obvious pretense of actually caring. The phrase is reminiscent of the corporate-speak companies use when accepting suggestions that they will no doubt ignore.
Joe: Obama is not an American! He has a Kenyan birth certificate! I demand he be removed from office immediately!