I'm not trying to prove you wrong. I'm complimenting the "rules" themselves. As far as bad behavior goes....I see the exact same behaviors coming from both extremes. Sloganeering, as you point out, is a waste of everyones time.
Ah! But you asked "[w]hy would a liberal or independent not use the same standards," not whether they should.
I have found that the way we speak or write often has a great effect upon how we think, and
vice versa. Try using a foreign accent all day and see if you don't notice small changes in your perception and thinking.
I am of the opinion that they won't use my rules, because in so doing they'd have to change the mode of their thought, and that tends to be frightening, often humbling, and always a lot of trouble.
And notice that our perceptions are altered by the way in which others speak. Hollywood certainly has. Why else would so many characters in movies, for no apparent reason, speak with an English accent whether they are the master criminal, the master spies, the surgeon, the madman, the mad scientists, the scientist who has to explain to the hero, the hero, the ambassador, the advanced space alien, the vampire, the vampire killer, the supposedly French Starship Captain, the ancient Pharaoh, the ancient Greek, the ancient Roman, the emperor, the eastern potentate, the Mother Abbess, the harlot, the sophisticated lover, the compassionate nurse, the assassin, the mythical god of any culture or the avant-garde artist?
I am quite fond of the English generally, and an admirer of English and British culture as a whole. But I think that England never produced enough Englishmen to fill all the English-accented roles in all of our movies.