As an ageing old man, I have yet to see horse flesh being sold for human consumption although during the second world war and for some years afterwards it was sold as edible meat.
Likewise you will not see whalemeat on sale in the UK.
It is a cultural issue and any cook offering horse, whale, dog or cat's meat would
Soon be struck off the visiting list. We Brits are also fussy about which fish we eat and also which wild bird meat.
But despite these cultural idiosyncracies you can enjoy offal in the form of - liver, kidneys, hearts and in the case of sheep and pig, their brains. Old fashioned traditional cuisine is still to be discovered even in the twenty first century. We eat certain offals in my house.
But regarding horse meat:
If my horse were to die or be put down, then the carcass would most likely be collected by the local fox hunt and fed to the hounds.
Alternatively at great expense, the horse'c carcass can be incinerated.
It is still possible to get permission for a horse to be buried on private land but some local governments withhold permission since in some low lying areas it is undersirable to pollute the water table with rotting flesh.
All horses nowadays are supposed to be registered with passports which contain details of all the drugs which may have been administered by a vet and which might have rendered the flesh inedible by humans after euthanasia. This system has the effect that relatively little horse meat can be considered for human consumption.
Except in wartime, there is rarely a shortage of food in Britain and there is plenty of meat of all types to eat without needing to consider horse flesh.
If you know where to hunt, there is a lot of game meat - venison, rabbit, hare pheasant or pidgeon.
But I suspect the fundamental issue in this thread is that I have yet to meet a Brit who would choose to eat horse flesh - especially if it previously had been
Kept as a riding horse.
Likewise we are reluctant to eat a pot bellied pig, or a courtyard chicken kept primarily for eggs, or a pet dog or a cat (which when skinned looks remarkably like wild rabbit (which we do eat).
If this subject relates to the over population of wild mustangs in the US, then the problem does not apply in Britain. There are relatively few areas on the island of Great Britain where wild horses roam unfettered. Most of the open land is to be found in the national parks - the Highlands, the Lake District, The Cambrian Mountains etc, each of which are managed by wardens, who would not tolerate too many wild 'ponies'. On Dartmoor, from time to time the ponies are rounded up and shipped off alive to France - where the French do eat horse meat. There might be a market for an American to airfreight frozen horsemeat to France - if the EU strict regulations could be met. The French eat a lot of unusual foods - including snails (delicious if done in garlic butter)
But please, keep your eyes off my tubby Irish mare. She's not for eating - ever.