Winning or losing a lawsuit of this type is not necessarily proof of guilt, or proof that roundup causes cancer. what it proves is that a jury was convinced that it does.
And we get guilt wrong in criminal trials all the time (see the number of people the Innocence Project has gotten off of death row because the person didn't do it). A jury saying one thing doesn't make it objective truth.
Roughly 90% accuracy. And the burden of proof is lower in civil cases.
Which isn't to say that a civil trial verdict isn't accurate to some extent - it just isn't absolute proof. There's some evidence in scientific literature about roundup's carcinogenicity at high doses (like what a farmer or landscaper would commonly encounter) and other various health issues at high dose. The big question is what happens at low doses and if it's impactful. The science is still out on that (and the alternative of lower agricultural output per unit of land area isn't really palatable from both a starvation risk perspective and a climate perspective).
No we don't. In criminal law the burden of proof is "beyond reasonable doubt". The bar is set much lower in civil law with the plaintiff only needing to demonstrate a "preponderance of evidence".
