I'm not criticizing the players. I'm criticizing the creative staff at GW and the concept of laughter being part of anything such as strife. They are wrong today, and were wrong 25 years ago. They fell in the same pit hole as many before them (comic book writers, Poe as you mentioned and many others) whos minds deemed it plausible for laughter and struggle to be combined from the vantage point of a comfortable chair.
Sure you can just say it is because Nurgle wills it, but that is an explanation only fit for a child, it takes away all intentions from every minor daemon and make them non factor. Laughing is a luxury that can be afforded no one struggling.