Why do gangsters say woo?

Excuse me, could you please clarify what you mean by "gangsters saying woo"? It's an interesting phrase, but it's not commonly associated with the world of organized crime or gangs in my knowledge. Could you provide some context or explain further what you're referring to? Are you perhaps referring to a specific slang term or a cultural expression used by gang members? It would be helpful to have a clearer understanding of the situation in order to provide an accurate and relevant answer.