Non binary means violating the binary. Drag is predicated on a binary existing. It plays with the idea of the binary. The point of drag is poking fun at the opposite gender. The opposite only exists because of the binary.
A trans person isn’t non-binary either. More importantly, a drag queen isn’t an identity. It’s someone who dresses like a woman as a joke. Conchita is a character, not the same as the person. If I get on stage and play Othello, am I now Othello? No, I played the character. That’s not me.