Partly true. cow is beef, pig is pork, sheep is mutton (but rarely if ever eaten), but lamb is always lamb, never mutton, otherwise "mutton dressed as lamb" would make no sense.
Venison is still venison, (who's ever heard of buying "dear meat"?) Chicken was always chicken as a meat, "poultry" refers to the livestock as a collective noun.
I beg you to go to your local butcher (or butcher's counter in your supermarket if you don't have a butcher) and order a kilo of "swine flesh" and see how widespread that usage is!
Whoever wrote the section of the wikipedia article you quoted clearly doesn't speak English as a native language, or was having a joke at your expense.
Mutton has been a normal food in many times and places. It happens to be out of fashion in most of the English-speaking world right now.
I grew up around sheep and often ate mutton as a child. To me, calling young mutton “lamb” has unpleasant connotations. It would be like calling the meat of a relatively young pig “piglet”, or the meat of a relatively young chicken “chick”.
Close but not exactly. In farming contexts, piglets and chicks are often distinguished from pigs and chickens precisely because they’re too young to eat. So “young pig” really does mean something different from “piglet” in this case, in the way that in many contexts “young man” clearly means something older than “boy” does.
Regardless of your opinion on eating meat, I don’t think this is a failure of euphemism so much as an accidental dysphemism.
I heard "deer meat" relatively often in Georgia and Alabama, when I lived there.
Also, while he said "swine flesh" was widespread, he also said it was widespread in a religious context -- that is, pejoratively -- so that would explain the reaction you'll get at the butchers'. I confess that I heard "swine" quite a lot in church, when I was a churchgoer.
Venison is still venison, (who's ever heard of buying "dear meat"?) Chicken was always chicken as a meat, "poultry" refers to the livestock as a collective noun.
I beg you to go to your local butcher (or butcher's counter in your supermarket if you don't have a butcher) and order a kilo of "swine flesh" and see how widespread that usage is!
Whoever wrote the section of the wikipedia article you quoted clearly doesn't speak English as a native language, or was having a joke at your expense.