>Now, as someone who has organized events with speakers, I must admit I would not appreciate if someone had been invited to give a talk on one thing and then takes half the time to talk about how someone else is wrong (with a subtext of "I am right") instead. I have a certain desire for reliability when I'm organizing things and I would feel let down someone did this to me.

>My concern with having such talks - regardless of that Joel does not mind - is that I would worry about sending a message of "give a talk, have your points ripped into pieces 2 years later" to speakers who might be less happy to have that done to them.

That's a legitimate concern. However, Joel Grus' talk was about all the reasons he did not like Jupyter notebooks. Would you not consider a talk about all the reason Jeremy Howard likes Jupyter notebooks to be a step towards symmetry, fairness, and a fun way to engage debate.

I did not see it as ripping apart someone's work, as I didn't see Joel Grus' talk as ripping apart the Jupyter Project's people's work apart. In my opinion, that was a refined and fun way of disagreeing, and if I would love to be able to do that, or have it done to my content in such a way.