Rich, I think the reason you're not getting any further responses to your repeated question on the same topic is that anyone who had anything to say on this topic has already said it.
Tone of voice is essential for understanding sarcasm. Reading a transcription of what was said will never tell us what was meant.
It's even possible they learned a lot in the lesson and the person is unhappy because he thought they spent too much time on the subject or covered it too thoroughly.
If you asked someone what time it was, and he told you the time zone in every major city in Europe including where you were standing, you could say "Well, that was a thorough answer. I certainly know what time it is now!" to your friend afterwards. It could have the same intention is the statements you use.
I'm also unable to imagine the laugh at the end for either a positive or negative meaning.
Student or Learner