Now, organic chemicals including rotenone, pyrethrum, etc. can still be bad for you, but they are much less harmful than synthetic ones (See my article on "Organic Products. Dangerous?" dated May 20, 2001). And you can wear gloves and masks while using them and prevent harming yourself. The main difference is that synthetic stick around for years and years and organic ones stick around a few days, maybe a few weeks at most and then are broken down into harmless particles.
I take Environmental history in school right now and I have done reports on cultures that have ruined their land and are now starving because they cannot grow food in their dry, arid conditions seemingly man-made conditions. Most of this environment occured because of deforestation and artificial irrigation but the effects are the same....death and destruction. Now I will give climate it's due here because the climate in a dry area would have some effect on the inability for population to sustain itself. However, this is because the people back then did not know how to adapt their crops to this type climate. Life thus far has been trial and error but now that so much money exchanges hands, it's tough to revert back to a more nature friendly method if a loss of money will occur.
Here in America, we have thought to fix all our problems by creating chemicals to make our lives easier. Our efforts to make hairspray, cleaning fluids, gasoline, weed killers, etc., have polluted our water supply. There really isn't that much fresh unpolluted water left to meet the needs of our population growth. Heck, even flouride that is put into toothpaste is a toxic waste by-product. Ever notice the warning on a toothpaste box? Ever wonder why it's there? That's what they don't tell you. Same thing with aspartame and probably saccharin too. (This info comes from my studies of Stevia, an herbal sweetener which the government will not allow as a sweetener. It's called a dietary supplement instead. Just look up Stevia on the internet for info.)
Just as trees freshen our air (notice how much smog there is in areas? Not enough trees.), our water such as that in Anniston, Alabama, has been polluted all in the name of convenience, power, and financial gain. Do you think the owners of Monsanto really care about those it sells its products to? As long as you keep lining their pockets with money, they could care less. They can buy bottled water just like the next guy. At least until there is no more clean water and then they may have to rethink their water polluting ways.
