With greater image saturation thanks to various internet services, plus the social aspects of many of these services, people are more concerned, and perhaps more aware of the issue of privacy. The problem is they confuse or over estimate their privacy and personality rights and forget that the act of photography in public does not violate these (in many countries - seems things get a bit tricky in some places like France and Germany, for example). It's how the images will subsequently be used that can become the issue. It's easier to try to shut down the act of photography than to trust the photographer will abide by legal image use, over which there is no easy, direct control by them.
I really do feel there is a greater suspicion of how images will be used. That is the question I have most often been asked.
Compounding this, as mentioned above, is paranoia about terrorism, etc.
Meanwhile there is a proliferation of security cameras, your phone tracks your location, advertisers know your preferences better than you do yourself... People are increasingly aware of all these intrusions in their lives, but they're all faceless and/or massive entities. The photographer is out there, alone, visible, and easy to target as yet another irritant in modern life, over which the offended subject can at least feel to have some direct influence.