There were clearly attention-seeking non-questions presented as questions in my larger university lectures (1). They were not good questions, and could accurately be described as bad questions or really just non-questions. You see the same kind of people grab the mic during Q&A at conferences and proceed to pontificate without any real question.

The (2) case is sort of nuanced, sure. I think there were sort of two cases of "dumb" question here: (2a) the person really just hasn't been paying attention and asked a question covered earlier in the same lecture, potentially even quite recently; if they didn't understand it, they should have asked when it was introduced, and if they weren't paying attention, they should've been. And (2b), remedial-type questions, which would be good in a class prior to the current one, but just demonstrate that the asker isn't ready for the course they're in.

These are bad questions for everyone else in lecture, who get to be distracted and sidelined from learning.

I didn't get the impression that anyone was throwing freebie questions to the professor to invite more questions from the tentative, but that's just my anecdotal experience.

What makes for good questions? I think good questions are timely and on-topic — relevant to recently discussed material. Save the questions about homework for after (or before) class, or office hours.