There's a big plus side for using Roundup (and the like) — soil conservation. No-till farming saves millions of tons of topsoil annually, and improves the soil in many other ways. No-till farming depends on the use of weed killers.
http://www.scientificamerican.com/article.cfm?id=no-till
As for what's “turning American males into Democrats” — birth control pills may have something to do with it (although that suggests that feminization and leftism go together; and that doesn't explain the growing number of very rational conservative women). If you want to mention hormones and birth control pills, you should also mention unfermented soy products. Soy milk, for instance, is loaded with so much phytoestergen that you'd be safer drinking ordinary milk, to wash down birth control pills.
Yeah, I hear ya over the impacts of tillage techniques being a complicated subject.