I Don't Know if This Definition Is Right for the Urban Dictionary: Petri Douche

First, see what they say at Urban Dictionary: Petri Douche:

"Petri Douche: A place/location where a lot of douchebags are known to congregate.

A place that attracts and seemingly breeds chavs/douchebags/jackwagons/etc etc."

'via Blog this'

It fits 'poetic' appropriateness, I suppose; but–considering that "Petri dish" (which 'Petri douche''s page doesn't specifically mention) is typically 'where the specimens are gathered (passive) for examination'–one can easily see 'a place where freaks-of-society are gathered for the public's viewing-pleasure and/or -for examination' as a more-correct definition.