I spent my life in public relations. I know that for everyone who gets the joke, there are ten others whose lives do not contain the knowledge base to understand that it is intended as a joke. They include, but are not limited to, persons born in states where there are no large Amish populations, persons who have recently joined America one way or another, and persons younger than 40, who have already been indoctrinated to think that all Christians are evil, and especially anyone who dresses modestly.
Repetition engraves carelessly evil thoughts into the minds of people who lack the foreknowledge to repel the invasion. It is the basis of advertising, which is one of the most successful techniques in our economy.
Perhaps you are too young to remember the rash of "Polish" jokes that once defamed an entire ethnic group and nation soon after the N-word was finally recognized as socially unacceptable. That craze took about 30 years to extinguish, and is still around on the Internet. Yet the Poles have been among our staunchest allies not only in the Middle Eastern wars, but also in the culture wars.
But mostly, the Amish comparison is simply not funny. Over and over again, it's boring, rude and ignorant. As another FReeper recently said, some jokes are funny once; some are funny always. Trust me, this one's fifteen minutes are over. It was funny never.
Oh come on, man! It’s not a slight against the Amish, and I think most people, even non-freepers, will get why we use it. It’s to illustrate the fact that most of these crimes we’re dealing with involve two politically protected demographic groups (and don’t kid yourself, we all know which two they are). So the Amish reference is used to show how ridiculous the media covers for these ‘groups’ by not referencing their backgrounds.
You have the sense of humor of a Liberal: “OMG, you’re defaming a protected minority group!”