Please David, when you see some differences in the meaning, between classical and medieval Latin, let us know. It's interesting.
I like the drunk parrots, but I also wish to learn about how Romans lived, and the Horace texts in this course. We had lararium, paedagogi, patrons and garum, as notions about how they lived, and that is very good, but I hope there will be more.
I had a year of very basic classical Latin in high school (pretty much useless; I remember a textbook with stories about a family in Pompeii) and did buy a paperback Wheelock to study on my own. However, since I didn't start formal Latin studies until grad school, I was never seriously exposed to the rarified literary Augustan Latin they shove down undergrads' throats.
Based solely on this course, I have to assume that drunk parrots and rampant weasels are common tropes in the works of Ovid and Horace. ;)
In short, it isn't: scio is enough. However, as the rest of the sentence is referring to our opinion, rather than mine/my, it helps to emphasise the contrast.
Paraphrased, it might be understood as: At least I know our opinion, how come you guys are singing so off-message...?