I dont mind if they put horsemeat in burgers - the estimated 10-20,000 fly grazed/dumped/unwanted horses in the uk would be best put to this purpose.
However, I mind VERY much not being aware of what is in food, and find it extremely disturbing that horsemeat is in these burgers. Pig DNA too, but that could have been because of the factory also handling pork (tho not ideal for Jewish/Muslim customers), but there is no reason why horsemeat should have been there. From a food security and safety point of view, it is unacceptable.