Supposedly because the Coptic women were "dressed inappropriately." But in reality, this was yet another assertion of power and supremacism over the Christians by the Muslims in Egypt.
"Angry mob bars church goers in Beni Suef," by Luiz Sanchez from Daily News Egypt, October 28 (thanks to Twostellas):
A large mob in the village of Ezbet Marco, in the Beni Suef governorate, gathered around the only Coptic Church in the area on Sunday morning, forbidding Copts from neighbouring villages from entering the church.
According to Ishak Ibrahim, a journalist and researcher at the Egyptian Initiative for Personal Rights, two Copts were injured as a result of violence brought about by the predominantly conservative Muslim crowd barring the entrance.
As the church is the only church in the area, it is very hard for Copts in neighbouring villages to pray elsewhere. As the mob maintained their blockade of the church skirmishes occurred, and two Copts identified by Ibrahim as Sobhi Saleh and Ibrahim Sadeq reportedly suffered from fractured arms and feet. Cars were also damaged in the scuffle.
“During Ramadan priests and Copts from Ezbet Marco were asked to not allow Copts from outside the village to pray in the church because the Muslims in the area believe they dress inappropriately,” Ibrahim added. The women’s attire does not conform to traditional dress.
The police surrounded the church to protect it from being attacked and, according to eyewitnesses that had spoken to Ibrahim, managed to diffuse the situation and arrest some people suspected of participating in the mob.
“This is not only a problem in this village,” Ibrahim said. “It is a big problem across Egypt.” Two months ago, in the Al-Amareya district in Alexandria, Muslims demanded the local church refuse to receive Christians from outside the village. “What can the people do,” Ibrahim said. “They don’t have [a] church in their area and therefore must go to nearby villages that do have one.”
Ibrahim asserts that it is the right of every citizen in Egypt to be allowed to have faith and practice what he or she believes. “The state in turn has the duty to protect them and their right to practice their beliefs,” he said. The rhetoric offered by the government, according to Ibrahim, is that there are not enough Christians in such areas to justify the construction of new churches and so the Copts from surrounding villages have no other choice than to make the journey to the neighbouring villages.
Ibrahim demanded the government and President Mohamed Morsy work to resolve the issue surrounding church building, in order to allow Christians to build their places of worship with the same rights as Muslims.
Currently mosques may be built virtually anywhere and with little interference from the government, but Copts require written permission from the government before they are allowed to build, and are often met with a rejection.