First, I didn't read the talk or look at the slide. I'm not a software developer and I work in a profession that frequently deals with the public and government.
There are lot of people here trying to turn this into some sort of culture war, either people forcing X values on others, or people from Y culture implying Y culture is correct and X culture is bad and even a little of Z culture implying everyone is wack and that culture shouldn't be relevant and both Y and X just plain suck. From my perspective aside from this all being rather silly and ignorant of living and working in a multi-cultural world the key point is being ignored.
If you want to have conference with broad participation and support you need to declare the ground rules and abide those rules regardless what the rules apply to or who they affect. By ignoring a stated policy or having no policy the result will be companies and people not attending the conference. If you won't abide your own policy there is little point to the whole thing.
Regardless of your personal opinion on the validity of cultural offenses the fact remains if you enact a policy that allows offensive behavior in a culture the result will be that a significant portion of that community from that culture and the businesses from that culture won't attend and provide support. If you enact a policy that forbid a behavior or imagery that a culture finds offensive then presentations with such content are provided you will be publicly endangering the support and attendance from those that culture.
Can you imagine the damage you could do to the support form a business from culture Z if the owner/manager finds out that offensive behavior for culture Z was prominent and expected at the conference? The key point here is that unless you want this to be a private conference with limited attendance only from the culture and people who feel exactly like you do then feel free to engage in talks and presentations that other cultures find offensive.
But if on the other hand you want broad attendance and support you better create a policy and abide that policy or you might as well write the conference off because in the long run business support and attendance will drop off the face of the earth. There are a number of FOSS conferences that no longer exist, I'd argue primarily for that reason. IBM and governments aren't going to support or send employees to conferences where sexual material is presented and that's a fact. Arguing that US culture is wrong doesn't change that fact and just moves to point out your own biases.
If you want an example look above. We've already got a post by a person representing a government supported agency saying that they've been burned twice now and they are going to consider carefully whether they support the conference next year. Do that enough and you won't have sponsors and attendance will fall off. There is a reason it's called business standards, if you want to do business in this world and don't abide those standards you are going to offend a lot of people from a variety of cultures and you won't be in business anymore.
If someone displayed a BDSM image (nudity or no) at a conference in my profession their career would likely be over, and I mean go get a degree in something else and start over in some other career dead. It astounds me just how out of touch with the standards in the rest of the business world software development appears to be. Maybe I'm wrong.