Oh No! our neighbor died!
This is a meme, but also a joke. There are a few reasons why this is funny. First and foremost, Karen is misunderstood by the man in the joke. He thought she said "hooray!", which would certainly be inappropriate if your neighbor died unless your neighbor was a horrible person.
Another reason why this is funny is how inappropriate it would be to say "hooray" as a response to the announcement that someone died. That would be super rude, and rudeness is funny. His prim and proper response to her is also pretty funny - it juxtaposes nicely with her perceived super rudeness.
The pictures that they used for the people in the meme are pretty funny as well, their faces look so happy for discussing such a grisly topic. There is a dissonance there that is humorous.
Finally, this meme seems to refer to other memes (though the similarities may be coincidental) - Karen as a name for a irascible white lady is pretty common, so perhaps this is a Karen, and not just some lady named Karen. Additionally, the way that he is about to sip his beverage at the end reminds us of that judging Kermit meme entitled "but that's none of my business".
All in all, this is a funny meme. Certainly worth the free-fifty that I spent on it.