Why Christians blame Atheism for taking out of school prayers?
The first case was by Jews (Engel) and the second one is a Unitarian Universalism (Schempp). Murry O'Hair case was consolidated by the Schempp case and well publicized.
There are other similar cases about prayer before these cases.
Usually, a religious sect disagree another sect's prayer such as the Catholics.
"From time to time, religious minorities would object to the particular observance performed in the local schools. For instance, in the Edgerton Bible Case (Weiss v. District Board (1890), the Wisconsin Supreme Court ruled in favor of Catholics, who challenged the use of the King James Bible (developed by a Protestant country) in Wisconsin public schools. This ruling was based on the state constitution and only applied in Wisconsin, but, like other challenges elsewhere in the country, provided a precedent for later federal rulings"
Why blame the atheist when it has been going on before 1963?
the court just took hers out of many cases and well publicized.