A friend of mine told me that yesterday, he ran into Shua Novoseller, the owner of the gym in Lakewood, and asked him about exactly what happened with the Zumba class.
Shua told him that the true facts were actually not stated properly. Most of the Rabbis in Lakewood actually had no problem with it. In particular, he mentioned R’ Matisyahu Salomon, and said that he had no issues with it. He did say that there was one big Rabbi (who he declined to name) who was adamantly opposed to it, and was trying to shut down the class.
Ultimately, R’ Salomon had told him that he should just make a business decision. If he felt he’d gain more customers by shutting down the class, he should do that. If more people would stay/join with the class, then keep it. Shua ultimately decided to shut down the class.
My friend asked him how it affected his business. He said that the month after shutting the class, they had more people sign up than any other month. However, they also had many people cancel their memberships over it.
One thing Shua did mention was that many of the women who left still wanted a Zumba class, and ended up going to non-Jewish, mixed gyms. This just goes to show that once again, adding unnecessary chumros ends up causing more harm than good, and pushes people away.