I think you are missing the point of the article. Obviously, just like he stated in his article, not all Poles speak like this, but the ones in the UK do because they are village boys in the big city and these idiots give a bad name to the rest of the Poles who don't speak like this.
non-lower class Poles rarely do such things but I guess "expats" with inferiority complex need to boost their funny ego with such garbage.
I am married to a Pole. "non lower class" as you call it. No ego, just facts and the article is not wrong.
How exactly do you tell a non-lower class Pole from a regular Pole? Blokersi with money are still lower class, you do know that right? They just have clothing with names on them with the hopes of making others jealous but they still drop the k word.