The reason NN aren't considered Lemon Glazing is because they are an approach towards at least one of the known models that does produce intelligence- you. Of course, backprop and self organizing maps are far less complicated than the events in a single rat neuron. Of course, computer simulations of neurons and neural networks are based upon the purely logical framework of the CPU and RAM. Of course, the recognized logical states of all of those hardware components are abstractions laid upon a complex physical system. I don't quite say irreducible complexity, but, at the least, immense complexity at some level is required to produce what we recognize as intelligence.