There is no doubt that information regarding religions must be taught in schools. After all, religions has been a significant social force that has shaped the history of humanity over the millennia.
The crucial aspect is the approach with which religion is taught. What definitely needs to be avoided is to use religion education as an excuse to persuade students of the validity of religion, that is in essence, to preach religion.
Religion must be taught as a factor in historical and social context - a bit like how extinct religions like the Mayan or Norse religions are studied. It is all right to inform students of Mayan sacrifices to serpent gods or the hammer of Thor that was believed to created lightning and thunder. It helps to understand why the Mayan and Norse societies behaved in the way they did. However, to suggest today that these such sacrifices or divine hammers have anything to do with meteorological reality is criminal brainwashing of students. Unfortunately, the same standard is not applied to extant religions.
And even more unfortunately, it is difficult to maintain this fine line of distinction due to limited resources that education systems around the world have. With the exception of mathematics, even subjects that deal with reality such as geography, history and science are taught with some degree of belief on the part of the student. This is obviously so because it is not possible for every student in the world to be shown evidence of plate tectonics , or historical artifacts or even certain scientific experiments. Thus, the way we learn for the most part in schools today is by believing that even though we have not personally observed and examined the evidence, it exists with the experts.
In such an educational environment, it is very dangerous to simultaneously introduce a subject which has no evidence for it…because it might incite a student to believe a myth as true, assuming that some guru or saint has the evidence for it.
I therefore think that due to the pragmatic limitations of the educations system, it is prudent to keep religion (theology) out of schools. This is a topic best suited for matured adults in Universities.