We’re doing things twice weekly now, so get ready for things to get obscure once in a while: Forty years ago last week, a notorious radio station stunt turned a Chicago baseball game into a war zone that left American popular music fandom with an ugly memory for decades — and that some say helped change the course of pop culture history for the worse. That event was known as the “Disco Demolition riots.” But did badly behaved fans get too much of the attention for a bigger social phenomenon… and is the same mistake of focus happening today?