What Makes Neural Networks Fragile

What do the images below have in common? Most readers will quickly catch on that they are all seats, as in places to sit. It may have taken you less than a second to recognize this common characteristic. If I heed Andrew Ng's suggestion that anything a human can do in less than a second can be automated by a Neural Network, then I should be able to create an image classifier that recognizes seats. I could write a standard classifier using off-the-shelf python libraries.