This is very interesting. My travels in Egypt touched on this.
I was suprised to learn that Egyptians consider belly dancing an Egyptian tradition. Their society is largely conservative Muslims & Christians, yet they overlook the immodest aspects of belly dancing because they proudly hold it as part of their heritage. It's an interesting paradox of modern Egyptian culture.
I don't know if belly dancing originated in Egypt, but Egyptians think it did.
There are other similar, interesting paradoxes in Egyptian culture. They have one company that brews beer even though the vast majority of their society holds drinking alcohol as taboo. It's sold almost exclusively to tourists, but they do allow it.
Another intersting thing is gambling. When I was there, the President's(dictator's) brother was the only person in the country permitted to operate casinos. His casino in Teba near the Israeli border was bombed to bits a couple of years ago. The largely conservative society is anti-gambling, but the dictator has a tight enough grip on power that he can allow his brother(& only his brother) to make huge profits from it.
It's becoming more dangerous for Western tourists there, but I highly recomend a visit if you're up to the risk.
EDIT: I noticed you mentioned harems, too. The Western notion of harems probably comes from the vast harems the Ottoman sultans were reported to have.
I've never heard a Muslim claim that belly dancing & harems are myths.
in our special dinners called ''Fasil''(basicly dinner with alchol and traditional music) we still have belly-dancers (dansöz) also some parts men bellydances (zenne) still exist but it not approval by us
