So why does the right gin up faux outrage over a joke or a scarf? Because they can force a change in the outward actions of someone who is not at the moment in their control and get a response. They are validated. Therefore, they do it because they can do it and because it shows everybody that they have that kind of power.
"We can make your life a living hell an we will for no or for damn little reason if we want to." Actually, normally the reasons are fake or they are just there to show the rest of us that they can and they will if you or you choose to cross them. Or as I say with the Duncan Donuts Rachel Ray thing just to show you what they can do.
The Letterman thing was obviously a joke about an adult who got knocked up and now holds herself out as an abstinence spokes person. Why is she not a reasonable target of sarcasm? Answer she is, but the right cannot allow it so they must attack.
The other part of that is that they are given the space on the news and teevee to bloviate. Then there seems to be somebody who claims to be progressive always saying well perhaps our person was a little out of line, the joke sexist, that Frost kid shouldn't have been put out there by his parents.
Then the right goes on attacking someone else. Hell maybe I do live in the end times.