I think you're answering your own questions. Would you ever really expect anything like this to actually happen? No. So it would tough to even tell anyone what you saw, because you know they would think you were crazy. Also most of us (and them) would believe the government can come in and take control. It might be rough for awhile, riots, lot's of people getting sick, people dying, but eventually the military will get it under control.
The other thing to remember about TWD and I assume FTWD is that according to Kirkman there was no Romero in their world. No Dawn of the Dead, no Night of the Living Dead, no Zombieland, etc. There weren't comics and movies about zombies in their world. (i.e. this is a fictional LA, Georgia, etc.) Hence why nobody calls them zombies in the shows (or comics). So people coming back to life and how to kill them would be new to them. (as opposed to us, who've seen movies and shows, etc.)