Part of the problem – and it is a problem if food is being sold under false pretences – is that no one is testing for horse DNA or, indeed, for pork in beef products etc. Food is tested for safety but not necessarily for authenticity – different agencies are now responsible since the coalition government came to power.
I suspect that our general cultural rejection of horsemeat dates right back to the days of the Norsemen. We accept that it is illogical to refuse horsemeat when we eat beef, pork and lamb, but we see horses in a different, nobler light from cattle, pigs and sheep.