@Bob, now you're gonna get me started too!!
What we have in the US is not a democracy (direct rule by the people, Athenian-forum-pottery-shard style), but a republic; which means we rely upon the clowns we habitually send to legislatures to represent our interests. Therein lies the problem.
[Probably the biggest reason for the very high US incarceration rates is our idiotic, failed "War on Drugs". No less a conservative than William F. Buckley (R.I.P.)---who might have been expected to do just the opposite---supported the decriminalization/legalization of drugs because, more than the drugs themselves, he feared the police state the W.O.D. would justify for its prosecution. Some parallels there with the War on Terror, which at least has a real enemy to combat. But that's a digression....]
Politicians of all stripes seek to increase their power and influence, and longevity in office. In the US and elsewhere, that means buying influence and votes by distributing other people's money to favored groups. Politicians, like humans everywhere, respond to incentives to act in their own best interest, and we have thus incentivized them. Point is, don't expect politicians to do the right thing, when the expedient thing is close at hand and entails offending relatively few affected individuals. What is certain is that another major terrorist attack, at least in the US, will bring severe political consequences for whomever is in office at the time; whereas hassling a few photographers has little downside, and on the miniscule chance that someone thus hassled turns out to be covered in plutonium dust, the cops and everyone up the line are heroes, and the pols will be first in line at the press conference to grab the laurels.
In defense of law enforcement, it's not always the cop on the beat at fault. Leadership of metro police departments is frequently poor, evidently; chiefs are chosen for political reasons rather than for law-enforcement professionalism. The beat cops don't always have the guidance they should about what to do. It is maddening, though, that after several highly publicized incidents, the word still hasn't filtered down.
I've been accosted by police on a few occasions; my experience has been that a polite answer to their queries, maybe an explanation of what I'm up to with those strange cameras that don't look like the usual tourist digicams, has resolved the situation. It's more frequently occurred that I've been bothered by some obnoxious rent-a-cop security type trying to prevent my photographing something in plain view from public property. I am large, and therefore more intimidating than my actual toughness would warrant
, so no physical confrontations have occurred. I have had to school more than one such Barney wannabe on privacy-rights expectations in public, and remind him that he can be charged with assault and/or theft by trying for my film.
Even more aggravating are those individuals who don't think they should be photographed out in public. I photographed some skateboarders once at our local extreme skate park; one had fallen and was injured--broken wrist, not life threatening--and paramedics were on scene when I arrived. I photographed those proceedings from a distance, impeding no one's aiding the kid, and was obnoxiously dressed down by some woman in his entourage. My polite responses to her failed to get rid of her, so I eventually had to answer in kind, demeaning myself but making her go away.
So it goes....There's a point somewhere in the preceding; anyone finding it, please report to the Principal's office!