DbD Derangement Syndrome refers to the medically diagnosed condition affecting many ex-Dead by Daylight players, that although no longer play the game, still willingly choose to stick around community hubs to criticize the game, it's developers and any community figures for any perceived wrong-doing, regardless of how minor, causing great annoyance to any current players who just wish these people would leave them alone.
"I hope this game goes under soon, there's not a single game I wish to see die so badly. DbD doesnt deserve its fame or money"
"Didn't you stop playing months ago?"
"Yeah, I haven't touched it for a year."
"Man, you really suffer from some severe DbD Derangement Syndrome."