I think the issue is the mis-labelling, not the content. The ingredients clearly state 63% beef, 10% onion and the rest made up of sweepings off the floor and wood shavings etc. Nowhere did it mention horse or pig, that is the issue. I will happily eat horse, I've had a fair few steaks and enjoyed them, but thats not the point. The shitstorm Tesco are finding themselves in is because people have now lost confidence in their labelling, why buy a 95% pork sausage for example when it may only contain 60% regardless? Sure it may be 95% 'meat', but why would you even believe that if they lie about the animals involved? What about those little wheel doohickey things that tell you how healthy it is, was that based on reported ingredients or actual ones? Is all labelling bollocks, or is that just the meatballs?
It doesn't help that the british public are strangely sqeemish about different animal body parts anyway, so throwing in a whole new animal too will turn some peoples stomachs. The funny thing is there aren't enough horses knocking about to make all the burgers 30% horse FFS, it must have been a spare one they chucked in for good measure and they got unlucky. I'd suspect Dalepack* are going to the wall for this, will any supermarket touch them now?
* At least I think it was Dalepack?