Calling the PM a 'cuck' is a classless slander against his spouse, and not against him. 

Nonetheless, profanity does serve a useful purpose. It's an efficient way to point out someone's shortcomings and show contempt for them, while leaving their wives out of it. For example, one might refer to the PM as Prime Minister Zoolander. That quickly describes his shortcomings without doing any injury to his wife.

To make things even easier, someday the word 'liberal' will take its place in the lexicon of profanity. That word will come to mean something far worse than 'cuck,' or any other swear word beginning with the letters 'cu.'