it raises the question of why the X-Wings don’t pass through the shields the same way the Falcon does.
I’d assume for the same reason the X-wings don’t also exploit the hyperspace loophole - both methods would be almost suicidal even if your ship is as tricked-out as the Falcon. No way Leia would risk the entire fleet like that, and probably wouldn’t have even agreed for Han to try if he had told her beforehand.