That's because the asserts are sometimes self-contradictory and often nonsensical in other ways.
X is a letter. Y is a letter. Both are true. In mathematical equations X and Y can also represent numbers. That is also true. The onus on you is not to prove or disprove others' positions. As the author of the o the onus is on you to prove your own position. As I stated b4, you might prove my pov incorrect but that would not, in and of itself, prove your position correct unless X and Y are the only two possibilities.... er, I mean, options

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Or repetitive.
X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y,X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y,X&Y, X&Y, X&Y,X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y, X&Y.................
Yeah, yeah, I get it. X&Y. Next!