No. Religion as a sociologcal phenomenon is, or could be, a subject of pretty serious science [sociology, in its non-PC variant]. Some of religion aspects [the teaching of the world, for example] could be swept under the pseudosciences, though. Thus, it all depends - on what aspects one is dealing with. Some of these are dead serious, others not at all. And since the aspects of interest are precisely the serious ones and not the abstruse questions like the number of angels capable of simultaneously dancing on the tip of the needle, or the symbolism of episcopal vestments, to sweep it all into pseudosciences would be erroneous.