The problem with completely dropping zoning is you end up with situations like the West fertilizer plant, where a building stuffed with explosives was placed next to a two schools and a retirement home.
Well, when you give up a little liberty/property rights for a little 'safety' you get a whole lot of inflexible shit in return. Zoning and its inflexibility hurts the people on the bottom of the totem pole the most as the article indicates. With no zoning, you can still have a lot of shit, but at least you're not married to it.