I have to say I don't agree with this assessment. I don't think that scepticism is committed to the notion that knowledge requires complete certainty. (And note, by the way, that the word "certainty" is dangerously ambiguous to start with.) It certainly isn't committed to the notion that we know nothing at all, something that only the very most extreme sceptics, such as Arcesilaus and perhaps Pyrrho, asserted. Scepticism merely says that there are some things that we think we know, which in fact we don't. That's not such a crazy claim. To make it, you don't have to set the standards for knowledge unattainably high - you just have to set them higher than some of our beliefs reach.
I must also point out that, historically speaking, scepticism has often been used not to argue that we know nothing (or even that we know relatively little) but to argue that our knowledge is not based upon reason. This was the basic approach of religious sceptics (by which I mean philosophers who used the arguments of scepticism in support of traditional religious faith) in the seventeenth and eighteenth centuries. They thought that we know all sorts of things - but we know them by faith, not by reason, because the arguments of scepticism show that reason won't get you very far.
This is interesting...earlier on in probably a different religious tradition than that you are describing, wasn't a big part of Aquinas that even though divine law came to us through revelation, we could still contemplate natural law through reason and that we had the ability to moral self-perfect ourselves through God-given free will? Either Augustine or Aquinas said that this was the case with Aristotle and that he did not go to hell for this reason. How did this change into what you are describing in later thinkers?