I am looking for a verb (or phrasal verbs) for describing the act of someone who seemingly speaks confidently on a topic he/she isn't actually sure of (he/she knows it inside). It is not like "bullshitting" because that person sounds like he/she actually knows stuff and is able to fool people (but in reality is just making bold claims, promises, spilling unsubstantiated facts walking in circle in retrospect). It is usually coming out of someone who is an "elite" in society, or is trained/experienced in public speaking.
I suggest "pontificate." In the example provided the writer completes by means of adverbials the sense of speaking confidently about things the person does not master or should not speak about:
What these interviews generally come down to is an invitation to writers to pontificate upon things for which it is either unseemly for them to speak (the quality of their own work) or upon which they are unfit to judge (the state of the cosmos). — Joseph Epstein