Let's say you're out with two friends discussing the war on drugs, with all kinds of rational, civilized debate on the science, politics, economics, sociology, etc. Suddenly, one friend declares, "Ok, I understand the risks and potential rewards, and I've decided to start dealing coke." Sure, you can try to calmly talk them out of it, and/or you could do some "ranting." Both would be appropriate.
"Hivemind" indeed.