Naturally, more girls like dancing as compared to men. What motivate men to attend dance class? If you are single (like me), probably you would like to meet some girls there, or to learn dancing in order to dance with a girl, or just to find a hobby (why not sports?). If you were in a relationship (not married), you might join because your girl friend is in the dance class. It is quite possible you are dragged into the class because you girl friend need a dance partner and she likes you to join as well (good for the relationship anyway). That's the reason you see some guys who are not very enthusiast in the class. If your girl friend is very pretty or you feel rather insecure, you might join as well just to "protect" her from other predator (the single). These guys may not be very enthusiastic as well. Then you got the married man, who would not join a dance class because their wives are in it. They might join if they really like dancing.
No matter you join dancing for whatever reason, try to take it easy and you would like it eventually. How long you would like it is another matter :)