we're the only place in Europe that has them
My meaning of exit check is the same as the government's. If I'm taking the Eurostar from London, before I get on the train I need to show my passport to the French guy only (well, 2 years ago - not sure about now), in order to enter the Schengen area. If I'm taking it from Paris I need to show it to the French guy to leave the Schengen area, and then to the British guy in order to enter the UK. What is wrong with showing it to a British guy before leaving? Someone said:
who has a think about whether they will allow you to proceed
But no, they don't "have a think". If they see a EU passport, they just make sure that it is you in the photo and then its "have a nice trip". It's the same when you're coming in - may be even easier as you have to sort yourselves out into lines at the airports. They don't stamp anything and certainly don't log the fact that you left the UK on a computer. (I guess the airline has already done it, but the airlines did it before they started the exit checks anyway)
OK, so now name me a country that doesn't do that besides the UK. The Schengen area is a single country for this purpose, as are the British Isles. The point of these checks is to make sure that any foreigner is not overstaying. And they only way to know if someone is a foreigner or not is to make everyone show their passport. They are not even going to challenge foreigners - except to log any overstayers, who will not be allowed back in and if they apply for a new visa it may be refused. There is nothing and never will be anything anywhere about needing to get what would be called an "exit visa", for example like they had in the Soviet Union, unless the UK leaves the EU and "unsigns" the Declaration of Human Rights.