I'm not defending his presentation; that slide offends me too. But I know that he deserves better than to wake up seeing this on the front page of Hacker News.
The author could have used the slide as a jumping off point for greater issues like gender equality in tech, or the pros and cons of being offensive in a presentation, or even a discussion about the word "bitch". Any of those topics would have forwarded the point more than writing a long ad hominem attack on someone who surely didn't intend to hurt or offend anyone personally.