The same way that if you and I were standing in the subway discussing the finer points of <topic potentially offensive to people on the same railcar> or cracking stupid jokes regarding the requirement for some software to have a dongle.
Just because someone in that crowd can be offended by something we say doesn't mean jack shit, unless it is directed directly at them I don't see how it applies to them.
That's entirely a matter of opinion. I think you're wrong. PyCon's code of conduct does too. I think adding a clause about not public shaming is good though. These comments were creating an environment that reasonably made someone uncomfortable. PyCon's updated policy gives people a safe and productive way to deal with it. There's still a risk it'll leak out (as it often does), but it at least lets everyone know what the expectations are.
Just because someone in that crowd can be offended by something we say doesn't mean jack shit, unless it is directed directly at them I don't see how it applies to them.