I didn't attend the talk, but I did download and look at the slides. If someone at my workplace (or, any Australian workplace) gave a talk using that imagery, it would be seen as both inappropriate and unprofessional. I'm almost certain it violates the sexual harassment policy of my employer.
I don't see how the slides can be defended. They're certainly offensive to some people, and any argument that they're necessary is clearly rot - I think we can communicate a technical message, and provide emphasis and energy without that particular imagery.
The argument that it'd be fine on Australian broadcast TV doesn't hold much muster either. You can choose not to watch TV, and you watch that for a different reason than you attend a technical conference. To go to a conference you have to agree with what's shown on television?
Clearly people were upset by the content of the talk. I've read through the mailing list discussions and seen some suggestion that the offended people should just leave. That's not exactly inclusive - people pay to attend a conference and then have to opt out of the keynotes? Other people suggested that those that were offended should have spoken up. That's definitely something that's easy to do if you're already in the minority. Sure, the marginalised should always confront power, that's easy, right?