[JohnBooty]

  "if we are able to accept a sketch on tv mentioning a
  dongle in good humour, why is it a sackable offence 
  within earshot of someone?"

I don't have an opinion on whether or not it should be sackable/firable, but there's a big difference between something on television and something in real life.

Would you really see no difference between your mother hearing a penis joke on television and a stranger telling her one on a train?

If you hear a joke you don't like on television, you change the channel and maybe don't watch that show again. Somebody's making sexualized conversation you don't want to hear in public, it's not always fair/convenient/possible for you to leave. In the case of the PyCon thing, perhaps Adria could have handled it better, but why should she have to give up her seat and leave the presentation (or even go to a worse seat) because she doesn't want to hear the guys behind her making sexual jokes?

[jonjwlee]

But he's not telling it to her, is he?

If he was telling it to her she would have every right to feel offended and report to the authorities. But that's not the case here.

If you made a penis joke to a friend, would you want — or indeed, expect — to be fired for it?