Bicycles on the Sidewalk

Bicycles should not be allowed on the sidewalk, if the cyclist is an adult. The road is where an adult cyclist should be, because they are considered a vehicle. Being someone who walks places a large majority of places, I'm often freaked out when a bike whizzes up from behind me on the sidewalk, with no bell or any indication that they're coming.
The road is where bikes are meant to be. I have nothing against them, I think they are a wonderful and more environmentally friendly alternative to driving cars. But they need to be on the road.
On my hour walk home from school, I pass by a group of about four or five guys on bikes who take up the whole sidewalk on their bikes. I am the one moving out of the way for them. It wouldn't be a problem if they were on the road to begin with. It is especially a problem with elderly people, who I see moving off of the sidewalk for the sake of these cyclists.
In a way though, I find myself sympathizing with the cyclists of Waterloo because we are in desperate need of more bike lanes that actually lead places instead of being dead ends. If there were more useful bike lanes, I'm sure more cyclists would take to the road.