Lawyers and police are at high risk of suffering delusions of grandeur. They regularly attempt to interpret the law themselves and will continue repeating and enforcing their version of the law until a judge (hopefully) stops them.
In this case the lawyer is saying that public disclosure of documents related to an ongoing case are hindering the courts ability to make a sound decision. Those involved in the case could have their opinions swayed after reading public/expert commentary on the matter. By undermining the courts ability to rule fairly those who released the information are in contempt.
Basically the lawyer thinks that his case is at risk if he loses control of the narrative and the flow of information. Is the release of that information an act of contempt? I've got no idea. But I do know that if the judge determines the release of the Information was wrong then an appeal of any decision is guaranteed and nothing substantial will happen in the case for years.
This whole mess could very well prevent Snapchat from selling all or part of itself until the case is final and all appeals have been heard. Law prohibits the sale or transfer of goods with disputed ownership. Then again maybe that's what this '3rd founder' wants. Perhaps he's angry and is trying to scuttle everything.