Please don't take this personally, but this line of thinking is just plain stupid. There are crazy animals just like there are crazy people.

In the context of bears, looking at populations as a whole, bear encounters are rare. Most people have never seen one in the wild and never will. For those of us who get out and enjoy the fresh air, the chances go up. I've encountered several in the wild and never had a problem with them. But with 6 billion people on the planet, there are a fair number of folks missing some marbles. There are some animals out there, including bears, missing some marbles as well.

Some animals are more aggressive than others, even without the human factor. Granted, animals can be conditioned based on their environment. But that doesn't mean there aren't some bad apples out there that can't cause problems on their first human encounter. People do need a better understanding, but people also take the quickest answer and treate it like doctrine.

I've posted this before, but I still think it makes for an interesting read:

http://fwp.mt.gov/mtoutdoors/downloads/BearAttack.pdf
http://www.nps.gov/glac/parknews/news10-05.htm

Keep hiking...