This morning, a crowd gathered near the Supreme Court to protest the weed-killer Roundup. Inside, justices heard arguments for Monsanto v. Durnell , weighing whether to exempt the company that created Roundup from lawsuits alleging that it failed to warn users that its herbicide causes cancer. Outside, the protesters rehearsed long-running grievances against Monsanto: One man was passing out flyers about “the hidden truth” of genetically modified food, and one speaker railed against “Mon-Satan.”