What double standard? There are outspoken liberals and outspoken conservatives. Neither is more shunned or rejected than the other. Neither are being denied their freedom of speech. Both get laughed at by both side's political opposites.
If anything, the double standard seems to be that when a liberal says anything publicly they are told its not the proper time and place. Or that they need to fall in line else they're not American, like post 9/11 with Bush.