We have a frequent flyer patient at our hospital who has aphasia, a brain condition which causes nonsense words to come out instead of what the person was intending to say.
We have a NO idea what this person is saying, but his tone of voice and delivery are completely normal even though the content of the words are meaningless. So I can confirm, this guy cracks jokes and is hilarious (he laughs at his own jokes and you can't help but laugh with him.)
The German memes feel similar. I don't understand the words, but the intent is clear enough for me to enjoy seeing them.