I think that most people don't recognize the harm that these memes can cause. Most don't see them consciously at all. I realized at some point that I am what I label a "compulsive reader". When I see a sign, it intrudes into my perception and I have to read it. Many people don't even consciously see these words/signs. It is important to realize that not all brains work the same when weighing the costs of allowing theses intrusions.