Whats the difference between free beer and free lap dances?
#1) Every event I have ever been to that offered free beer also had a variety of other drinks for people who don't like beer or don't consume alcohol.
#2) I have never been to a professional event where watching people drink is an acceptable form of entertainment.
#3) If you don't drink you can simply decline. If you don't want to watch a lap dace the best you can do is leave the room. That's not, in my opinion, a reasonable thing to expect people to do during a conference.
#4) It is socially acceptable to have a few drinks in a public setting while having a lap dance is generally not.
I have no issues with adult entertainment. I don't buy the line that it is exploitation but things have a time and a place and a developers conference is not it. I am sure there was more then one person there who did not appreciate it. The fact that no one stopped to think that it may not be appropriate for the venue shows at very least a lack of taste from the event planners.