A friend posted this mini-rant on Facebook earlier, and I agree with his sentiments wholeheartedly:
Quote from Miłosz G.
In AD 732, the Pope has decided that horse meat consumption has to stop because it was largely associated with pagan practice*. While the ban was largely involved in some regions of Europe (and, in fact, the ban was a factor that somewhat slowed the religious conversion of the continent), others decided to abide by it quite strictly. Among those others were the fine people of states such as the Kingdom of East Anglia, Mercia, Wessex, Northumbria, Connaught, and so on.
Skipping a millennium or so (+/-100 years), we are now looking at the British Empire and its expansion to, well, everywhere. With the Britons' territorial expansion came the spread of culture, including the "horse meat is no good" dogma (which, as is the case with most dogma, is at this point considered to be the universal truth).
Let's skip a few more hundred years, we're now in 2013. The British Empire is now a collection of sovereign states best described by the term "Anglosphere". Despite many important disagreements between these countries (e.g. "how do you pronounce the word 'zebra'?" or 'should I nest single quotes within double quotes, or is it the other way around?'), they are largely in consensus about a particular societal tidbit - the idea that horse meat is terrible.
Every now and then, people are struck with an outrageous incident where someone sells horse meat as "beef". Why is this an outrage? Logically, I can see why people would be pissed off about buying something and finding out that it's not what it was advertised as - I'd be pissed off as well if this happened to me. To my surprise, however, that's a very rare complaint from the victims of these events. The most common issue appears to be that people have eaten horse meat, and that horse meat is very bad in taste. Now, please pardon my naïvety, but if the meat was particularly repulsive, wouldn't you notice that... while eating said meat? I mean, I've had bad meat in my life, and I've also had horse meat. The two don't correlate much at all.
The Anglosphere is stuck with a taboo that's developed over the past millennium through what I can only assume to be an incredibly long series of simplifications and misinterpretations. Somehow, the Anglophone community made its way from "Horse meat is evil, because pagans eat it" ("Horses shouldn't be eaten because they're our friends" was a somewhat common argument too, I suppose) to "Horse meat tastes very bad".
If you have your doubts about this, go and get a kabanos (http://en.wikipedia.org/wiki/Kabanos). They'll have them at your local Polish shop (note: shopkeeper not guaranteed to speak English. Please consult your instruction Manuel for details). Or, you know, go out there and buy some cheap Lasagne. I'm sure there still are plenty of brands selling "contaminated" "beef" out "there".
TL;DR version: What people should be outraged about is that they're not getting what they paid for, not that it's horse meat. There's nothing wrong with horse meat. Quit being bitches about it.