I think it has more to do with our aging boomer UK mentality. My grandma used to and mum still does, cook the life out of everything.

Those generation's have very high paranoia about food borne illnesses and bacteria.

They believe if pork isn't cooked to a chalk consistency you WILL die. "Bloody" steak? You will also die. Ground beef must be cooked to the point of resembling cigarette ashes...or you'll die.

However, you will find many places in Canada where medium-rare burgers are typical. I worked for a fairly large chain restaurant in Ontario that would cook them medium rare unless specifically requested otherwise.