Opium for the people?

I remember once being in Peter, took a tour of the temples. So everywhere the group was introduced inside, and the mosque was not allowed, say not Muslims can not enter. The most crazy thing in the synagogue was: everywhere ads that it is forbidden to photograph, but right next to the sign that for 500 rubles you can.

It is interesting, and in the places of predominance of Muslims in the mosque and so allowed, and excursions are conducted. Probably, in Peter they fear that the spirit of Muslims in the mosque will weaken if unbelievers are allowed there.