A yuppie who does not consider themselves to be a yuppie because they hang around a crowd of upper-middle class hipsters and "punks". They got into Marx and feminazism at college and consider themselves to be revolutionaries because of this, despite the fact that they work for, live like, and are like capitalist yuppie scum. The "pink" part of this term refers to the fact that these people like to enjoy the privileges of being hip, selfish yuppie brats, even though they claim to be all for equality under communism/socialism (which, if you listen to anything they say, comes across as thinly veiled fascism).
That pink yuppie thinks Joe Blow is a rapist snuff-pornographer because she heard some bullshit about him from her friends and because he wants to make underground movies. They all love movies like "Bloodsucking Freaks" and "Desperate Living", but they're going to try and get him beat up by some lunkheaded motherfuckers who do what they're told like dogs. To her and her friends, it's only a small victory of the SOCIALIST REVOLUTION!