I do think though that there is a difference between making a felony a misdemeanor versus flat-out making it not a prosecute-able crime.
I'm not all that familiar with California's legislation, but I don't think Prop. 47 completely decriminalizes these acts. It just moves them from felony to misdemeanor. You can still be prosecuted for these crimes, but you're a lot less likely to end up incarcerated.
I can see no possible problem with telling people that stealing $1000 worth of someone else's property (at a time) is no more serious than a parking ticket. I mean, these are good people and they add so much to our communities.