It's the one about some of the Levitical prohibitions - there's even an icon that references it.
And it's WRONG. YES. Someone is WRONG on the internet. And so, of course, I must correct it.
This time, it's not the "making fun of people who actually practice it." This time it's getting the actual facts wrong.
David Shuster is saying that the other referenced prohibitions - mixed fibers, mixed plowing, mixed gardens (note a theme here?) rate the death penalty. Um, not so much.
The icon (as I said - they're WRONG! WRONG, I say!) says that the prohibition against mixed fibers is a prohibition against *man-made* fibers. This is more amusing than anything else. Ignoring the fact that all fibers are manmade, because none of them are usable in their natural state, we have this progression that shows why WRONGNESS needs to be corrected -
1. Someone reads a faulty translation of the Torah that says "mixed fibers" are forbidden.
2. Someone then assumes (reasonably) that means all mixed fibers, such as cotton/polyester, are forbidden.
3. Someone ELSE sees that and comes to the conclusion that POLYESTER is forbidden.
See the twisted path? The FACTS are that shatnez is very narrowly defined as sheep's wool and linen. Sheep's wool and cotton? Just fine. Cashmere and linen? Not a problem. (Person I know asked her rabbi if she could spin linen and mohair together. Yes, she could.) But the first mistake bred other mistakes, until you get the idea that acrylic brings the death penalty.
If you want to make a point (and this point has been made so often that it's almost meaningless), get the facts straight first. It means more.