Perhaps incomprehensible to you. I have never found them so. The point was not that differences have evolved. I was responding to your xenephobic rage at the very slight, surely comprehensible differences of our versus or spellings and the use of “ in hospital” as opposed to “in the hospital.”
It is not "xenephobic rage" (the word is xenophobic, BTW). I genuinely cannot read non-standard English without making mental corrections of the spelling and grammar. Doing this is tiring. This means that I very quickly get tired when I try to read British.
It is simply an observation that most British dialects are utterly incomprehensible. While I do not find "The Queen's English" very difficult, some of the other dialects--like Scottish, Irish, and Cockney--are not even recognizable as English. I think that most Americans--Canadians, too--would agree with me on this. Do not mistake my bluntness in stating my thoughts on the matter for rage--it isn't.
The people you see on TV shows or in movies are selected because their accents are mostly comprehensible, but try watching some of the reality shows, which are filmed in towns and feature people who are not actors. Those shows are subtitled because no one would understand them otherwise.