Maybe I don't understand democracy?

The Government of san Francisco is elected by the people. The government makes the laws. If the majority of the people there don't like the laws the government makes they can vote them out.

There certainly seems to be a "will of the people" thing going on here, or else that law would not exist..

>>"Candy, cookies and chewing gum are not harmful in moderation or harmful to others."--They are if you're diabetic.

No. They are OK in moderation for all but the most severe cases and eating candy does not harm others as does second hand smoke.

The watermelon thing is a non sequitur. the ban is about health, not about stereotypes.

As far as razor blades go, I think an appropriate line would be sale of a product with the good faith assumption that it will be used as intended. Obviously it would be wrong to ban the sale of gasoline because someone might douse themselves with it and light a smoke.

On the other hand. If the government of San Franciso want to ban it and the people support it by keeping them in power, that's their choice.