They are called FRUKE.
Actually most Chinese people can say the "L" sound. The Japanese find it harder because they have an "R" sound that is like a cross between an L and R (I always transliterate it as "R" but NHK always use "L", take your pick).
A cross between English /l/ and /r/ sounds. The Japanese sound is nowhere near a cross between, say, the Danish /l/ and /r/ sounds.
The worst one was in Team America. Koreans can say the L sound just fine. I know it was just a lame joke but really, if you are gonna be racist at least get it right.
Of course it was a joke. On a stereotype from the Anglosphere. Unfortunately you missed it and got all worked up in a fit of political correctness.