This is part of the classic The United Federation of "hold my beer, I got this" post chain. It's definitely part of my headcanon, if only in general spirit instead of literally that's-what-happened. It conveniently explains so much about why these shows focus so much on humans. It's like reality TV, it's pointless to focus the camera on the well-adjusted ones.
Edit: I should mention that my headcanon extends humanity's hold-my-bear mad science bent to the social sciences. Why else do you think we so rarely see other multi-species governments, or when we do it's just a boring old "boss species conquered a bunch of subordinate species"? Humans were probably warned by the Vulcans that different species tended to have incompatible governing interests and doctrines and the humans thought "but what if we gave them all a vote anyway and see what happens? Maybe a Federation will go twice as fast!"