"It's the dose that makes the poison" - that's a fairly accurate statement. Every industry uses chemicals that are potentially harmful, and we accept that as a trade-off for the benefits they offer.
The same applies to RoundUp. Is the benefit it offers to agriculture worth the risk? Can exposure be controlled in such a way that the risk is ameliorated? There's a cost-benefit analysis to be performed there.
Point is, stating that RoundUp is possibly carcinogenic is useful information – but it doesn't mean its better to immediately stop use of it. It also doesn't mean that Monsanto "knowingly market[ed] a poisonous, carcinogenic substance", as you stated. It does mean that use of the substance may potentially need to be re-evaluated, but preposterous jumping to conclusion of the sort you exhibited is what's killing political debate worldwide.
Water is not optional. Without it you die. Roundup is optional. Without it the world can still grow crops (we SOMEHOW have for thousands of generations). Dumping many many tons off chemicals designed to kill (however small the organism) all over our food and planet, let alone planting homogeneous, patented, and GM'd "basic" plants, is a recipe that likely isn't good for the planet over time.
Historical yields were tiny compared to what we get from contemporary farms. I don't know if we need Roundup in particular, but if we went back to traditional farming methods half the world would starve.
There's no going back.
Just by eating less meat (which makes sense because we are not supposed to eat so much meat), suddenly we don't need to product so much. The actual price of the food is so low currently that what you pay in a supermarket is mostly the externalities. Switching to cleaner methods would not lead to starvation providing that we would eat differently.
http://geneticliteracyproject.org/wp-content/uploads/2015/01...
You need to do a cost/benefit analysis, not reject methods that could cause any number of deaths ever.
Because all methods cause some number of deaths in some circumstances.
Numbers need context if you're going to make the right decision.
Your argument is almost literally "Stalin believed 2+2=4, therefore 2+2 is 5".
What a ludicrous position.