All They Needed Was an Excuse
The horror of having a brain full of holes might be abated by the infinitesimal chance of it happening. 'Mad Cow Disease', a nasty side-effect of bovine cannibalism, has a tiny chance of spreading to humans. But people have a tendency to guard against low-risk horrors when it is convenient to do so.
The desire to protect your local farmers is just barely held back by the benefits of free trade. If you can scare the public into only wanting meat from your cowboys, instead of their cowboys, your cowboys will be all the richer. So panic is a protectionist's best friend.
But it's not just the protectionists that need a good excuse. Beef is a bit of a guilty pleasure for people, especially increasingly flabby Americans. Sometimes we need just a wee bit of panic to at least temporarily eat something that has fewer human-compatible prions (and hopefully less fat) than beef.
I'll contemplate these issues over some locally grown, organic, fried chicken.