Well, if there's no-one else. For instance, "On June 5, 2005, Bob Jones came into my office and said he had evidence to exonerate my client, therefore, I think a court order compelling a deposition is necessary." There's no-one else who could say that.
But if you have lawyers actively engaging in the investigation of the case and then testifying what they found in an affidavit, it's kinda pushing it. There are rules of evidence, and someone has to testify about the veracity of the information. They've selectively printed certain messages, taking them out of context, to conclude, without anything but inferences that are a stretch, the KM actually created a false identity to take over a corporation. That's absurd.
By lodging the affidavits in that regard, they're subject to cross-examination such as, "There are other messages from Mr. Damage, isn't that correct?" "You didn't include the messages in this dialogue that would give us a full picture, isn't that correct?" "Mr. Major was responding to a question, isn't that correct?" "What message did Mr. Major respond to?"
I'm not saying they can't surf the web, but normally you get someone else, like a subpoena to investorshub and a sworn statement about the veracity of the messages.
Hell, I could make a false message and attach it to a declaration, "I found this on the web." Certainly, that would subject me to examination to find out if it's true or the context it was in.
In this case, the attorneys have made themselves witnesses.