Ferule and Fescue has a phrase for academia that made me laugh—“conference terrorism.”
I believe I coined this term last year to describe those aggressively bad papers that hold an entire room hostage while they're being delivered. But last night I saw a slightly different form of terrorism during the one panel I attended: during the Q&A a kindly-looking grey-haired man in the audience attacked every single member of the panel (two of whom were graduate students, one a second-year assistant professor) with very long, very hostile criticisms that weren't really questions. The panelists did an impressive job of parrying, but it was a deeply uncomfortable-making experience.
I would alter it slightly, though maybe this is discipline-specific. I care less about bad papers than I do bad presentations, which sometimes are of good papers. For example, no one should read their paper—or at least big chunks of it--which I see far too much. I would certainly give exceptions for graduate students as they get experience, but in general we should all be prepared enough to present a paper without reading anything but a few notes.
I totally agree with the second observation. I have seen many situations where an audience member seeks not to engage the author, or even to ask a question at all, but simply to air their own views, which also are often slightly off topic.