Why DO so many cyclists ride on the sidewalks?

From the Guelph (Ontario, I believe) Mercury.com, here's a piece by a runner who is sympathetic, certainly more than I am, to cyclists who for good reasons, maybe, have elected to ride illegally on the sidewalks. They ride there because they feel safer there.

They've become the scourge of pedestrian sidewalks, apparently all over North America.

Read the piece and decide for yourself: Are cyclists who want to feel safer (on the sidewalks) making urban life safer only for themselves? Or for nobody at all?

I vote the straight Nobody ticket.