I mean, he could have testified at the contempt hearing or presented any sort of evidence that he just plain forgot the password, and the court might have heard that. He opted to not testify or introduce any testimony at this hearing. So that court hearing did not seriously consider memory failure because the defendant did not seriously assert it.
(Of course if he was lying about the failure of his memory, that assertion might have gotten him into more hot water -- it would potentially be a perjury charge. But we should not say definitely "he was lying when he said that to police" but just "he didn't make that case for himself at court," if I'm reading these court documents right.)
Just to give the relevant excerpts, the supplemental order that the judge issued to explain his reason for the contempt order states that he's using a well-established legal framework for figuring out memory-failure type contempt cases, quoting one of those cases directly as:
> A civil contempt proceeding on a witness' asserted memory loss requires a three-step analysis that shifts the burden of production to the witness, but always leaves the burden of proof with the government. First, the government must make a prima facie[1] showing of contempt; i.e., that it made an authorized request for
information, that the information was relevant to the proceedings, that the information was not already in the possession of the government, and that the witness did not comply. Second, once the government has presented its prima facie case, the witness must provide some explanation on the record for his failure to comply. If the witness fails to meet this "burden of producing evidence," the government's prima facie case is sufficient to meet its burden of proof for a finding of contempt. The witness may meet his burden, however, where, as here, he testifies that he does not remember the events in question. Finally, if the witness meets his burden of production by claiming a loss of memory, the government must carry its burden of proof
for a finding of contempt by demonstrating that the witness in fact did remember the events in question, thereby establishing a willful
failure to comply.
Note that testifying "I don't remember the password" is enough to activate part two. The supplemental order then goes on to apply this in the only obvious way,
> [first, ] the Government's prima facie case of contempt was largely, if not entirely, uncontested ... [second, ] at the September 30th
Contempt Hearing, Mr. Rawls did not testify or call any witnesses, he did not offer any documentary or physical evidence into the record, and the only evidence he elicited was in the form of cross-examination of the Government's witnesses. Crucially, Mr. Rawls offered no on-the-record explanation for his present failure to comply with the August 27th Order... [therefore, ] in light of the Government satisfying its burden of proof, the Court adjudged Mr. Rawls to be in civil contempt of court.
[1] prima facie is a phrase which one might not be familiar with unless one has a philosophy or legal background; it means "at first glance" -- i.e. the government's showing might at a deeper stage be questioned but it has to "look like" contempt in order to start the process.