Why the name Xorcisten?

The name is chosen, because:

For those of you, who have wandered onto this site without really knowing what the XOR-operator is, I can assure you, that it has nothing whatsoever to do with dead chickens, black robes and incomprehensible mumbo-jumbo.

The XOR operator is the logical operator for the Exclusive-OR as opposed to the normal OR-operator meaning either-or-or-maybe-both (a little wishy-washy sort of statement in my opinion)
The truth table for the XOR operator is:

A B A XOR B
False False False
False True True
True False True
True True False