See, I keep trying to figure out how best to express the communication issue, because it's extremely important. The problem is trying to distill communication down to nifty, boxed rules just rarely seems to work. But maybe I can illustrate what I'm talking about better.
The problem with Rush playing around with words like "slut" or "prostitute" isn't "those words are offensive, you shouldn't use them because offending people is wrong". I think if there's one thing I've made clear on this blog and in pretty much every interaction I've had, it's that the Politeness Police are of zero concern to me. The polite word for an abortion is, say... "termination of an unwanted pregnancy". "Baby-slicing" is the impolite word. 9 out of 10 times in a conversation, I'm opting for the graphic, accurate words.
Nor is the problem, necessarily, that someone, anyone may tune out Rush for using those words. There are lost causes in conversation, or at least situational lost causes. The lifelong diehard liberal, who self-describes as a diehard liberal, and just has it in his head that all things labeled 'conservative' are wrong and must be opposed will be gravely offended if you call anyone a slut, and may well stop the conversation there. But that doesn't matter, because there is no "conversation" to be had with such a person anyway. They're there to represent, not converse. Two reasonable people may discuss whether Man X is guilty of murder, and there's a possibility one may change the other's mind, and end up saying "Alright, I think man X is guilty - but previously I thought he wasn't. I changed my mind." You will not get a defense lawyer to say this for obvious reasons. And you won't get people who approach a given topic like a defense lawyer to say this for equivalent reasons. You don't want to just piss this guy off necessarily - people change, people remember conversations months or years later in retrospect - but the fact is he's pretty low priority. In fact, if you go out of your way not to offend him, he will go out of hid way to find ways to be offended that are advantageous to him.
But what about the person - I suggest these are the vast majority of people - who may lean one way or the other on an issue, but in principle they may change their mind if you're persuasive? This is the one you have to worry about. This is a person who may be receptive to your arguments, even if they have a negative disposition towards your view to begin with for whatever reason. But they also may shut you out and not even listen if you say the wrong thing. Maybe he can be convinced that some given pro-union legislation is a bad idea - but his dad is a lifetime, proud, diehard union member. If you say "union workers are lazy shitsacks", you're done. You just insulted his dad, he's offended, he's not even listening anymore. It does not matter if you follow this up with a knock-down argument against the legislation, because he stopped listening as soon as you pissed him off, and now he may well back that bill out of spite, or for flimsy reasons he'll grab for because now the priority is sticking it to the group (you and your side) he doesn't like.
Now, you can dig in your heels and say, "If I offend him but I have the better argument, he's irrational and wrong for not conceding and changing his mind." Maybe. But it doesn't matter. And I suggest that if you privilege saying whatever you want without any concern of what effect it has, over and above actually getting people to listen to you, you're being irrational. At least if you value changing minds and advancing your cause. And if never, ever being careful with what you say is more valuable to you than accomplishing any real change, please quit bitching about "liberals" of all stripes, because you've already made it clear that their success is a price you're willing to pay to behave the way you are. Believe me when I say, liberals across the board pay attention to this sort of thing more often than not.
Maybe that's the lesson people are missing. If a poll shows that 52% of people are in favor of gay marriage, and 48% are opposed, and you are against gay marriage, how many people are your enemy? If you said 52%, you're wrong. That number subdivides into quite a spectrum: the diehards for whom this is just the most important issue ever, usually for irrational reasons, who will never change their mind barring a miracle. The people who never thought about it much but hey those gay guys on TV seemed nice enough and what's the harm? The people who don't really care but they have a gay friend and that girl will not shut up about this topic. In other words, of the 52%, you likely have a sizable number of people who in principle can and will change their minds about this topic if only you can reach them. But that's the trick - you have to reach them.
I'm going to end this one with an example I think is key. Westboro Baptist Church. They are extremely obnoxious and offensive. They rant on and on about how "God hates fags". Do you think "Gay Rights Groups" see WBC as a net asset or liability? In other words, "Is their cause advanced or held back by WBC's behavior?" There's no debate on this question - the answer is, they're an asset. Because WBC ends up being, for many people, the image of what it means to oppose Gay Marriage, etc. And it's a nasty image - a bunch of crazy hillbillies with no arguments, screaming their heads off and being obnoxious pricks. That association is absolutely loved, because for anyone who makes that association, the argument against gay "marriage", etc, is over immediately, and actual arguments will be dismissed. But the moment you understand why WBC, despite their superficial opposition to gay marriage, harms opponents of gay marriage... you're going to be armed with the logic that explains why you should choose your words carefully, particularly when you have an audience of Rush's size.
This is not an exhaustive treatment of this topic - that's not possible, it's human communication - but hey, maybe I've made one of my points on this sharper.