Packet discrimination based on the packet type or protocol (ie SIP/streaming video> http > ftp/smtp etc.) is fine and necessary, and while, strictly speaking, not neutral, it's also not really what net neutrality is about at it's core.
Net neutrality is mainly about source/destination neutrality, ie treating all traffic by the same rules, regardless of where it comes from or is going.
Analogies only serve to muddy the waters because they're imperfect in themselves. Instead of dumbing the subject down with analogies, we should be teaching the really rather simple broad concepts to the people involved.