Not to start a huge debate (although by reacting I'll probably will), but in my opinion...
Was Sagan's pinching: childish... yes, inappropriate... totally, sexist... yes (and the fact he didn't realize this while doing it, points at a wider society problem)
Do I think it's funny/ok that the organizers refer to the Sagan incident (which was - and this does play a part in me finding it ok - solved between the girl and Sagan afterwards)... yes
You should be able to make fun of just about everything, in this case there actually laughing - partly - with themselves as organisation (as they have done before in the past). Comedy can bring issues to the front, but doesn't mean that by bringing something as comedy, you take the side of the view of the easiest perceived way... on the contrary, a writer wouldn't use it, if he didn't see/feel the duality (or mostly even the other side) in it.
(Oh, and the comment "wie knijpt ze", does indeed literally translate to "who pinches them", but also figuratively "who is scared")