That's a pretty common response. I once asked some family members who are cops (three of them) if open carrying was legal. They all said that having ammo within arms reach was the same as loaded. Once I pointed out that that definition only applies to people engaged in gang activity one of them admitted that he had never ran into a non-felon with a gun on the street, so he didn't know. The other two stuck to their argument that it was illegal.
I'm not sure why this is a common belief with police officers. Bad_ace had a run-in with a Sheriff in Cupertino who thought the same thing. Another guy in a San Diego suburb was arrested and then un-arrested because the arresting officer "knew" he was right. It's some urban myth which has only reached cops. Luckily, having them read the laws makes it easier for your point to get across, although sometimes it isn't enough.