You are either far too old, far too young or just deluded... There is no 'Sinister side of Death Metal' just like there is no "Sinister side" of cheese Sandwiches...
Seriously.... There is always going to be people who just don't want others to have more fun than they are (not) having. My daughter has been playing this stuff. It really takes me back to my 90s metal/Alt metal days.... And its a good song too!
Lighten up. Enjoy the music!