They were quite overpaid compared to other local government roles, and had very poor public visibility. WP says they were originally going to be called "sheriffs" but that was rejected as "too American". This does make it clear that it was an attempt to copy the US system, but I feel obliged to point out that the Scottish court system has had Sheriffs for longer than the US has existed.
The French are just exercising their second amendment rights as originally envisioned by the founding fathers. They're doing America better than Americans!
Decades of reckless deregulation and -er- corporatism, the inevitable corporate consolidation that that behavior encourged, and "Stranger Danger!"-type fearmongering... I reckon.
The previously-super-illegal pervasive domestic surveillance programs sure don't help things, either. No cost is too high to stop "terror" at home and abroad, amirite? :(