What is the purpose of a stop sign?

I think my disagreement with a couple of friends—okay, more than a couple—stems from a disagreement about the purpose of a stop sign. For me, a stop sign is to prevent side street traffic from interfering with traffic on major thoroughfares. It could also be used to prevent accidents at intersections of two side streets, but a four-way stop sign should only be used in extreme circumstances—certainly not at nearly every intersection in a neighborhood, as is found in, say, West Rogers Park. A stop sign should not be used:
To protect a park, which has pedestrian traffic a few hours a day in warm-weather months
To protect a school, which has pedestrian traffic two hours a day, 180 days a year
To help people cross a major street. Illinois law already requires motorists to stop for pedestrians in crosswalks, so a stop sign is redundant.

As I’ve previously noted in this blog, Chicago residents whine to their aldermen about allegedly dangerous intersections. The alderman quickly install stop signs to placate the masses. Former Ald. Burt Natarus (42nd), whom I couldn’t stand, loved doing this. So did former Ald. Bernie Hansen (44th) and his successor, Ald. Tom Tunney. So does Ald. Bernie Stone (50th). Main thoroughfares that motorists once navigated rather quickly are now stop-and-go ordeals that are no better than side streets and often worse. I would support electric or temporary stop signs that were operational only when pedestrians were actually using the crosswalk. But a 24-7 stop sign is terribly unfair to motorists forced to stop and check for pedestrian traffic all hours of the day and night when there are precious few pedestrians to begin with. Why do commuters on their way to catch a train at 7:15am in the dead of winter need to stop for a playground stop sign? It’s ludicrous and a terrible imposition of government—the tyranny of a few determining the laws for the rest of us.
A few final notes:
Streets with bus routes should never have stop signs. That includes Touhy and California Avenues.
Aldermen should not have the right to install stop signs without expensive traffic studies that their budgets cannot afford.
Major streets with traffic lights should not have stop signs.
Streets with long stop sign-free stretches, like Touhy Avenue between Western Avenue and I-294 (9 mi.), should never have stop signs.
Stop signs waste motorists’ fuel and time and inflict more wear and tear on their vehicles. Government and neighborhood groups should be working together to remove stop signs, not install more. Fewer stop signs would mean the remaining stop signs receive more motorist compliance. As it stands, motorists pay less and less attention to stop signs as they continue to sprout like weeds around town. This makes our streets less safe for pedestrians—the opposite of the stated goal of the fanatical stop sign activists.