Laura Bush's character is certainly questionable. I understand, for example, that she does in fact drink milk (albeit cow's milk) and that she's even had sex with her husband. We need to run that hussie out of DC on a rail, then tar and feather the brazen bitch!
I didn't find the "joke" funny, nor appropriate for the first Lady of the United States. If you think otherwise, then fine. But YOUR opinion isn't gospel.