Speaking from a man's point of view and my experience with woman, I can honestly say that woman are just more open then men. Men are more stimulated by more things that make them laugh and get happy on personal level as opposed to a variety. For instance, I can remember an argument me and an ex-girlfriend had on me being anti social. Her example was that, why is it I could get so happy about cars and have the best time ever, but I couldn't get the same way about listening to her and friends gossip about people at work.
I think it is more than just "why women laugh more than men" more of why men and women just do most things different period. At the end of the day men and women are completely different and to fully understand the two takes time and patience, and I can speak from experience first hand. I show great homage to married couples who have been married for many years. It's very hard to constantly try to make the other sex show that you care about what makes them laugh and happy just as much as they do, but it's not impossible.
Men are just not as open as women are, and that goes further than just laughter, I would say emotions period. I don't think its something that we do on purpose, it's almost like were just made this way, sad to say. At the same time I don't think it's something that we can't work on. Some men feel weak when they expose themselves to laughing, just like some men will not cry. I think men are more conscious of holding themselves to a "macho" stand point, and do not want to come out of their shells.
Women on the other hand seem to be more open about every subject at hand. That is a great thing, and is something that men will never be able to achieve without fully acknowledging that it is ok to be just as open as the next person. I find myself coming out of my shell more and more not just for myself, but for the people in my life who love me to be as open as well. So from my experience it's not impossible to do, it just takes time and it's not something meant to change over night. Its just something that we all struggle with.
I'm sure we all can agree that that we can satisfy each other by putting ourselves in the other persons shoes sometimes. I think it is also on how you are raised as a child. Some men like to take on their father's role while growing up. For instance if your father wasn't the laughing type guy, we as men sometimes try to be the same way, but it only makes things worse in the end. It's better to pick and choose the good qualities from both parents, and try not to take on the bad ones. So in conclusion I think men want to laugh just as much as women, we just have to get to the point where we are comfortable with it.