There are tons of German dialects I would have trouble understanding as a German. Saying it's entitled to not be able to understand something like that is just far from reality if not ableist.

The picture is just a joke about the cultural hate of Scottish people against British people due to the history of these nations. It's not made to be taken seriously, but if you do… of course it's discrimination. I mean not the joke itself but what happens to the character in the joke. Like lol, it's literally because they are British. Trying to deny that is just ridiculous.