So? Both are public, a conference talk even more so. Make your speech offensive, expect people to react.
"I don't want my conference content modded by the speech police, thanks very much."
Someone's calling out rude behavior -> cry speech police. A little bit on the strawman side if you ask me. This guy wasn't censored, wasn't forcibly removed from the conference. The only consequence of his "joke" was someone expressing their disgust.
Right. Which is just shorthand for saying, "tomorrow morning nobody is going to remember this." People will just move on to the next outrage. If you don't think the speech is politically correct enough, stop attending the conference.
I think Stewart Lee says this much better than I would: https://www.youtube.com/watch?v=jGAOCVwLrXo