Perhaps it is a matter of logical symbolism which escapes you. Symbolic representations are not illusions, they are illustrations of natural constants. The symbol X stands for an unspecified thing, not for an illusion. Therefore to say that X is not X is denying the existence of the thing you are trying to represent.
An Equation is a mathematical and logical truth of a self-referential equality in values.
Symmetry: X = X = true.
p.s. It meets the logical law of "necessity and sufficiency"
And so it is with X.......