WikiLeaks Go-Between Takes the Fifth

Over at the mothership, Daniel Friedman reports on the latest in the Trump-Russia saga:

Randy Credico, a comedian and radio host who Trump adviser Roger Stone claims was his intermediary to WikiLeaks’ Julian Assange, has asserted his Fifth Amendment right ahead of an interview with the House Intelligence Committee that was scheduled for Friday, according to his lawyer.

….[Martin] Stolar said he was not aware of anything that Credico has to hide. But for the outspoken Credico, taking the Fifth “is the safest thing,” the attorney said….Stolar said that while Assange, who has been confined to the Ecuadorian Embassy in London since 2012, has called into Credico’s radio show as a guest, Credico wants to protect separate confidential conversations—“stuff that [Assange] didn’t talk about on the air”—that he had with WikiLeaks’ founder.

….“If they want to go charge Randy with something, then let them do it, not with his own words,” Stolar said. “I’m not saying he’s a criminal suspect in anything. But that is what the Fifth Amendment is for, to protect against self-incrimination.

Can I get an attorney to help me out here? I thought the Fifth Amendment could only be invoked on subjects that you genuinely thought might open you up to criminal prosecution. You can’t just invoke it across the board because you’re afraid you might blab something stupid. Nor can you invoke it to “protect confidential conversations.” Nor because it just generally seems like a safe thing to do.

Do I have this wrong? The House Intelligence Committee, which has released Credico from testifying, seems to be buying Stolar’s explanation pretty casually. What am I missing?